# Top 10 Things You Need to Know About Aspect Ratio, Screen Size, and Seating Distance



## p5browne

Black Bars are fine, as long as they just that - BLACK!


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## popalock

Scott Wilkinson said:


> 10. If you know your seating distance, you can calculate the optimum screen size you will need:
> 
> (screen height) = (seating distance)/3
> 
> For example, *if your seating distance is 10 feet (120 inches)*, the screen height for HD should be 40 inches, which translates to a diagonal measurement of 80 inches for 16:9 or 100 inches for 2.39:1. *For UHD/4K, the screen height should be 80 inches, which translates to a diagonal measurement of* 160 inches for 16:9 or *200 inches for 2.39:1*.


200" Scope for 10ft seating distance = Win!


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## NorthSky

I wonder how many people sit 4.4 feet from a 70" UHD TV? ...Can the brightness of the screen affect your eyes over time? 

For example; I sit 18 inches from my 15" screen laptop, and I know that my eyes get tired over time.

Back in the 50s-60s they were telling us to not sit close to our tube TVs; remember...our parents were telling us while playing on the carpet floor of the living room?
And I remember the couch being about 12 feet from a 25" tube cathode TV. 

Today we have smart phones with a 6-7" screen size or a tablet with a 10-12" screen size and we sit about 6 inches from it...from the recommendations we should sit much closer.
The screen brightness of our cell phones is getting right inside our eye's retinas and the radio micro-waves right in our brain.
I'm sure all for the best, as compared to the 50s.

Now UHD is here, and even in our laptops (12 to 17" screen sizes), and OLED and LED in the 55 to 75" sizes and we can sit only few inches from them for best imprint on our eyes...details. 

I'm invited to my neighbor's house to watch a UHD movie on Blu-ray ('Fury Road: Max Unchained'); we sit down, the screen is 105" diagonal, and our chairs are 6.6 feet from it.
...Times they are a changin'.


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## vaktmestern

So How close to sit from a 55" tv udhd and hd ? In mestric ?


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## Optimus_Fine

Scott Wilkinson said:


> 7. There are various formulas to calculate the optimum seating distance; for the purpose of this list, I will use the ITU (International Telecommunications Union) recommendation of 3 times the screen height for HD and 1.5 times the screen height for UHD/4K, regardless of the screen's aspect ratio.https://plus.google.com/+avsforum


I thought seating-distance-to-screen-height ratio's purpose was to give a correct perspective, since a flat image will look too steep at the sides when seen too close. 1.5 times is too big for a flat image.


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## prepress

I wouldn't want to sit so close that I get sick following motion across the screen. I am 9.5 ft. from the screen of my 50" Kuro and am not bothered by that distance, though at times I could see having another 5" of screen. Because the back wall is _right_ behind my head I may move the couch a few inches forward, but that's it. Placement options are very limited in this apartment.


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## Gary Lightfoot

Scott Wilkinson said:


> 7. There are various formulas to calculate the optimum seating distance; for the purpose of this list, I will use the ITU (International Telecommunications Union) recommendation of 3 times the screen height for HD and 1.5 times the screen height for UHD/4K, regardless of the screen's aspect ratio.
> 
> 8. The size of virtually all display screens is specified by their diagonal measurement. For 16:9 screens, the height is about half the diagonal measurement; for 2.39:1 screens, the height is about 0.4 times the diagonal measurement.
> 
> 9. If you know your screen size, you can calculate the optimum seating distance:
> 
> (seating distance) = 3 x (screen height)


That is a good starting point and documents like those from CEDIAs CEB23 or SMPTE for example suggest that; with a range of plus or minus one screen height (3x +or- 1x), so a range of 2 x SH to 4 x SH. 2xSH is where SMPTE recommend the closest seating distance should be, 4x the furthest.

Three times SH was also the Fox recommendation for film based on the crossover point where immersion (closer is better) and image quality (further means less arifacts) cross over.

However, THX looked at film stock and decided that 2.4 x the SH was the optimal viewing distance (3.68 xSH recommended for the back row), and it still is for HD. With a 2.35 screen, when viewed from the same seat/viewing distance, 16:9 will give you a 40 degree viewing angle and 2.35 around 52 degrees. Ideally you will be using an anamorphic lens to keep the vertical resolution the same, but image quality can depend on the tech being used (DLP, DiLA etc) and set up (reflectance level and calibration), so zooming can still be OK at closer seating distances. Or use a 4k display with good scaling for HD or 4k source material.

If the original design intent is important to you, scope should be the largest/widest aspect ratio (other than IMAX), with all others shown at the same height within it, in a constant image height presentation method.

With Sony's recommendation of 1.5 x SH for 4k/UHD, you should be aware that at that distance ratio, you may want to set your seating so that your eyes fall at around the center vertical or higher so that vertical viewing angles don't exceed the max recommended 35 degrees for comfort.

Gary


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## DrMichael

NorthSky said:


> I wonder how many people sit 4.4 feet from a 70" UHD TV? ...Can the brightness of the screen affect your eyes over time?
> 
> For example; I sit 18 inches from my 15" screen laptop, and I know that my eyes get tired over time.
> 
> Back in the 50s-60s they were telling us to not sit close to our tube TVs; remember...our parents were telling us while playing on the carpet floor of the living room?
> And I remember the couch being about 12 feet from a 25" tube cathode TV.
> 
> Today we have smart phones with a 6-7" screen size or a tablet with a 10-12" screen size and we sit about 6 inches from it...from the recommendations we should sit much closer.
> The screen brightness of our cell phones is getting right inside our eye's retinas and the radio micro-waves right in our brain.
> I'm sure all for the best, as compared to the 50s.
> 
> Now UHD is here, and even in our laptops (12 to 17" screen sizes), and OLED and LED in the 55 to 75" sizes and we can sit only few inches from them for best imprint on our eyes...details.
> 
> I'm invited to my neighbor's house to watch a UHD movie on Blu-ray ('Fury Road: Max Unchained'); we sit down, the screen is 105" diagonal, and our chairs are 6.6 feet from it.
> ...Times they are a changin'.


These are interesting points. There is a lot of research being done on Blue Light that is emitted by smart phones, tablets and televisions. It is very close to UV light on the wavelength spectrum and is being concluded that it causes eye strain and possible negative effects to the health of the eyes. 
As far as viewing distance there is a point at which eye strain will be an issue. Basically anything closer than 20 ft will demand the eyes to consistently focus to keep the image clear. This will bring about eye strain over time. In my professional opinion I always suggest sitting at least 8 ft away from the television.


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## Gary Lightfoot

With direct view displays (tvs, not projected images that are usually much larger), bias lighting can help prevent eyestrain.

Gary


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## 6athome

I've been telling my wife I need to replace my 55 inch with a 80 inch TV.
Now if I can only get her to read this article and agree.


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## p5browne

I think most people aren't worrying about the scientific method of where to sit. They just pick their spot, no matter where. If it's too close or too far away, they'll just re-position themselves to where they are most comfortable, and enjoy watching. (Like Sheldon on Big Bang Theory - now there's a guy that does it the scientific way!)


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## Rob-Houston

Scott Wilkinson said:


> ...
> 
> 3. ... learn to live with the black bars to see the image as the content creator intended.
> 
> ...


The very reason I avoided pan and scan movies. AND the reason I got a projector. Watching letterboxed movies on a 34" 4x3 just didn't cut it!


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## Scott Wilkinson

Gary Lightfoot said:


> With direct view displays (tvs, not projected images that are usually much larger), bias lighting can help prevent eyestrain.
> 
> Gary


Yep, that will be in my next top 10 list about the visual environment.


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## EvLee

DrMichael said:


> These are interesting points. There is a lot of research being done on Blue Light that is emitted by smart phones, tablets and televisions. It is very close to UV light on the wavelength spectrum and is being concluded that it causes eye strain and possible negative effects to the health of the eyes.
> As far as viewing distance there is a point at which eye strain will be an issue. Basically anything closer than 20 ft will demand the eyes to consistently focus to keep the image clear. This will bring about eye strain over time. In my professional opinion I always suggest sitting at least 8 ft away from the television.


The blue light hazard is not a simple catchall that encompasses all ranges of blue light. The main concern is with very short wavelength blue/near-violet in the neighborhood of 430 nm and below. If you look at Rec 2020 its blue is 467 nm, and you get plenty of that in natural daylight. Maybe some products use LEDs where there is more energy in the short wavelengths? At any rate, I agree you shouldn't sit in front of any display for hours on end without giving your eyes an opportunity for some rest, especially not that close.


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## IanR

Gary Lightfoot said:


> That is a good starting point and documents like thse from CEDIAs CEB23 or SMPTE for example suggest that; with a range of plus or minus one screen height, so a range of 1 x SH to 4 x SH. 2xSH is where SMPTE recommend the closest seating distance should be.
> 
> Three times SH was also the Fox recommendation for film based on the crossover point where immersion (closer is better) and image quality (further means less arifacts) cross over.
> 
> However, THX looked at film stock and decided that 2.4 x the SH was the optimal viewing distance (3.68 xSH recommended for the back row), and it still is for HD. With a 2.35 screen, when viewed from the same seat/viewing distance, 16:9 will give you a 40 degree viewing angle and 2.35 around 52 degrees. Ideally you will be using an anamorphic lens to keep the vertical resolution the same, but image quality can depend on the tech being used (DLP, DiLA etc) and set up (reflectance level and calibration), so zooming can still be OK at closer seating distances. Or use a 4k display with good scaling for HD or 4k source material.
> 
> If the original design intent is important to you, scope should be the largest/widest aspect ratio (other than IMAX), with all others shown at the same height within it, in a constant image height presentation method.
> 
> With Sony's recommendation of 1.5 x SH for 4k/UHD, you should be aware that at that distance ratio, you may want to set your seating so that your eyes fall at around the center vertical or higher so that vertical viewing angles don't exceed the max recommended 35 degrees for comfort.


It seems to me that we're mixing up the rationales for distance. In the past, the ratios have been different depending on resolution of the content/display .. ie. SD vs HD. But I thought the 40 degree recommendation (or 36) was largely determined by our field of vision and/or by the limits of 'immersion'. If that's the case, then the optimum distance should be independent of the resolution. With UHD and the 1.5 SH recommendation, I haven't done the math but it seems to me that you'd be violating the 36/40 degree viewing angle recommendation.


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## Daniel Chaves

I have a 120" 16:9 1080p screen and sit 9-10ft away and that feels perfect for me


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## Tom Riddle

vaktmestern said:


> So How close to sit from a 55" tv udhd and hd ? In mestric ?


2.3 meters for HD and 1.1 meters for UHD.


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## MSchu18

where is my twothirtynine screen... I am ready


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## Chase Payne

I think it should be mentioned that screen size does not matter, it really just shifts your seating distance. Everything takes a certain amount of space in your vision (called field of view) and regardless of the TV size or projector throw in the end if you sit at the recommended viewing distance that screen will take exactly the same amount of space in your vision regardless of the TV screen size. (This is because all TV's have a fixed resolution, so if you sit at the exact perfect acuity for the pixels, it ends up being the same field of view. This is why with virtual reality, you can get an experience equivalent to a 90+ inch TV because its so close to your eyes.)


So basically, a 28 inch screen at 2 feet is equivalent to a 120 inch screen at 8 feet.

Some people prefer sitting further away than really close, but if you can make a choice of sitting 1 feet closer to save several thousands of dollars (55 inch 4k vs 65 inch 4k depending on the screen technology) then it's worth mentioning this.



IanR said:


> It seems to me that we're mixing up the rationales for distance. In the past, the ratios have been different depending on resolution of the content/display .. ie. SD vs HD. But I thought the 40 degree recommendation (or 36) was largely determined by our field of vision and/or by the limits of 'immersion'. If that's the case, then the optimum distance should be independent of the resolution. With UHD and the 1.5 SH recommendation, I haven't done the math but it seems to me that you'd be violating the 36/40 degree viewing angle recommendation.


You are correct, the whole 30-40 degree field of view was designed specifically because our eyes are actually not that great at resolving detail beyond 40 degrees. This is precisely why when you go to a movie, while the movie in the theater is at 4k you may have notice your TV at home at 1080p looks sharper, that's only because movies are at 60-90 degrees field of view and 1080p sets are between 30-40 degrees. If you sit closer to your TV, all you're doing is reducing the clarity of your overall vision.



The best resolution for our field of view is actually somewhere around 1440p, or 1660p to be precise; so 4k is still an upgrade but only about 30% or so. Even if they fixed the field of view in 4k, we would still only be able to resolve around 1660p; the fixed field of view would just prevent us from losing overall clarity in the image.

But tread carefully, I have mentioned this many times and people have their own opinions on this. It always ends in a quote battle and fights.

Disclaimer: There is plenty of research on this online. If you want more details on this simply private message me. I don't want this thread to turn into a quote battle because many people are getting simply tired of the ranting against my claim.


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## NorthSky

DrMichael said:


> These are interesting points. There is a lot of research being done on Blue Light that is emitted by smart phones, tablets and televisions. It is very close to UV light on the wavelength spectrum and is being concluded that it causes eye strain and possible negative effects to the health of the eyes.
> As far as viewing distance there is a point at which eye strain will be an issue. Basically anything closer than 20 ft will demand the eyes to consistently focus to keep the image clear. This will bring about eye strain over time. In my professional opinion I always suggest sitting at least 8 ft away from the television.


I see in your sig that your HDTV is 65" diagonal. ...Eight feet (96") from it is good. ...Even for 3D Blu-rays. 
* Mine is 60", and I sit 7.5 feet (90") from it, on average. ...Seven feet minimum and eight feet maximum. ...I feel alright, I feel 3D. 

Top one thing you need to know about seating distance: *Take good care of your eyes first.*
Because they want you to buy big TVs and sit closer to them; good business for the TV industry, bad business for your eyes.
It reminds me back in the 50-60s the advertising for cigarettes. ...Look @ cancer today...we know the story...money first, health last.
And now they keep @ it but with the TVs this time. ...And tomorrow eye's doctors will be in short supply, and lawsuits filling our law courts. 

Yup, encourage people to damage their eyesight by corrupted TV advertisers/manufacturers and TV experts with sick recommendations. 
We live in a world of vices, non-stop, the capitalist way, and the healthcare system cannot keep up. 

What's more important? ...A huge OLED UHD TV, a big UHD front projector, or a good set of eyes to sleep better @ night and be able to see the mountains and eagles flying outside? 

Nice thread, with few important points missing. ...Are we blind?


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## beerhunt

*Use this 20-20-20 rule for eye care!*

While looking at display monitors & TV's...Every 20 minutes, look away from the monitor/TV's at anything at least 20 feet (58 meters) away for 20 seconds! I know this may seem unreasonable while watching an intriguing show/movie, but its easier to do than you think. Good habits are just as easy to learn as bad habits are!


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## NorthSky

You, an eye doctor?


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## fierce_gt

Scott Wilkinson said:


> 6. The other way for a 16:9 projector to fill a wide screen with a widescreen image is to use an anamorphic lens, which optically stretches the image horizontally while the projector electronically upscales the image vertically. For 16:9 content, the anamorphic lens can be moved out of the way, or in the case of a fixed lens, the projector can electronically scale the image to the correct aspect ratio. This approach is more expensive than zooming, *but it uses all the projector's pixels, giving the image more resolution* and making it brighter.


i've always had a 'philosophical' issue with this reasoning.

i'm a believer that resolution is really about the SOURCE and not how you manipulate it. just like watching dvd's on my 1080p tv is nowhere near the same as a true 1080p source, the minor upscaling done when using an a-lens is at best insignificant. 

sure there's technically more pixels displayed, but there's not going to be more detail in the image. and i'd argue that since it's no longer a 1:1 pixel mapping, you're probably getting less. kind of like how 720p content actually looks better on 720p displays than 1080p ones.

what we really need(ed) was for UHD to be a wider format. i'd love to have native 2.35:1 displays/projectors with a source to match that. now that i've experienced CIH, it's what i want for everything. the director can decide how wide the field of view is, but i want to decide on the height of the screen as that's how i perceive 'size'.


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## Star56

NorthSky said:


> I wonder how many people sit 4.4 feet from a 70" UHD TV? ...Can the brightness of the screen affect your eyes over time?
> 
> For example; I sit 18 inches from my 15" screen laptop, and I know that my eyes get tired over time.
> 
> Back in the 50s-60s they were telling us to not sit close to our tube TVs; remember...our parents were telling us while playing on the carpet floor of the living room?
> And I remember the couch being about 12 feet from a 25" tube cathode TV.
> 
> Today we have smart phones with a 6-7" screen size or a tablet with a 10-12" screen size and we sit about 6 inches from it...from the recommendations we should sit much closer.
> The screen brightness of our cell phones is getting right inside our eye's retinas and the radio micro-waves right in our brain.
> I'm sure all for the best, as compared to the 50s.
> 
> Now UHD is here, and even in our laptops (12 to 17" screen sizes), and OLED and LED in the 55 to 75" sizes and we can sit only few inches from them for best imprint on our eyes...details.
> 
> I'm invited to my neighbor's house to watch a UHD movie on Blu-ray ('Fury Road: Max Unchained'); we sit down, the screen is 105" diagonal, and our chairs are 6.6 feet from it.
> ...Times they are a changin'.


I love big, but if I sat 6.6 ft from my 106" it would be a miserable experience FOR ME. Your mileage may vary.


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## Star56

NorthSky said:


> I see in your sig that your HDTV is 65" diagonal. ...Eight feet (96") from it is good. ...Even for 3D Blu-rays.
> * Mine is 60", and I sit 7.5 feet (90") from it, on average. ...Seven feet minimum and eight feet maximum. ...I feel alright, I feel 3D.
> 
> Top one thing you need to know about seating distance: *Take good care of your eyes first.*
> Because they want you to buy big TVs and sit closer to them; good business for the TV industry, bad business for your eyes.
> It reminds me back in the 50-60s the advertising for cigarettes. ...Look @ cancer today...we know the story...money first, health last.
> And now they keep @ it but with the TVs this time. ...And tomorrow eye's doctors will be in short supply, and lawsuits filling our law courts.
> 
> Yup, encourage people to damage their eyesight by corrupted TV advertisers/manufacturers and TV experts with sick recommendations.
> We live in a world of vices, non-stop, the capitalist way, and the healthcare system cannot keep up.
> 
> What's more important? ...A huge OLED UHD TV, a big UHD front projector, or a good set of eyes to sleep better @ night and be able to see the mountains and eagles flying outside?
> 
> Nice thread, with few important points missing. ...Are we blind?


While I find some folks sitting distances to be absurdly close, there is not a shred of peer-reviewed evidence to support your nonsense about damaged eyesight.


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## Orbitron

Shouldn't there be one more measurement - the relationship of the vertical position of the screen/vertical head angle? A ceiling mounted screen that lowers, you are looking slightly upward, a fixed screen positioned where you are looking straight ahead.


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## granroth

Honestly, I look at the recommended distances as appropriate for watching TV, not movies. I want to be fully immersed into a film and sitting 3x the height puts me squarely in my second row. It's not bad to be there, but it's not even close to being as immersive as my front row.

The heuristic that works for me is to sit close enough that any closer will make you feel nauseous in quick motion scenes. I find that to be somewhat closer to 2x the height.


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## Mark12547

For me, 3x screen height works out about right.

However, for shakeycam (like The Blair Witch Project or Cloverfield), 6x screen height is too close.

On the other hand, when watching 2.35:1 material on the big TV, sometimes I wish for a bigger TV or a decent way to sit closer to the screen, which isn't practical the way my man cave is laid out.


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## <^..^>Smokey Joe

DrMichael said:


> These are interesting points. There is a lot of research being done on Blue Light that is emitted by smart phones, tablets and televisions. It is very close to UV light on the wavelength spectrum and is being concluded that it causes eye strain and possible negative effects to the health of the eyes.
> As far as viewing distance there is a point at which eye strain will be an issue. Basically anything closer than 20 ft will demand the eyes to consistently focus to keep the image clear. This will bring about eye strain over time. In my professional opinion I always suggest sitting at least 8 ft away from the television.


I've not measured UV light using a Jeti 1211 in any modern form of display. UV light is largely scattered by the upper atmosphere ozone layer, although some still gets through. People in the southern hemisphere who's ozone layer has a large hole in it from pollution can get eye damage from long out door exposure over a life time. FWIW if UV-B or C was coming from a display you could be blind in a relatively short space of time. OMG sunbeds!!!!
If someone was concerned all they need to do is wear clear plastic glasses as plastic absorbs a lot of UV light up to 300nm or so. I've tested this in the LAB and spectro which can read down to 190nm.


However a side note, which is related to field of view. The effects of flicker rates is of concern, the flicker filling the field of view and in some cases filling the peripheral viewing area as super wide viewing does can have health problems especially for those who have a sensitivity to flicker, which can be attributed to a vestibular disorder or photosensitive epilepsy. There are degrees to these things where many people don't know they have sensitivity at all.
For these people, the higher the frame rate the better for them, they also can be better off with a smaller screen size ratio and balanced room illumination.


I'm not a health professional, but the above is from medical papers related to this subject where the results lead to health warnings of 50/60hz fluorescent lighting, where now the standard install of this form of lighting is high 10~20000hz ballasts. People mistake the light source wavelengths as the problem, as with displays.


Pay attention to migraines or other eye/head problems that come about after viewing, if they continue seek professional advice. 


2c


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## NorthSky

Star56 said:


> I love big, but if I sat 6.6 ft from my 106" it would be a miserable experience FOR ME. Your mileage may vary.


That's the newest recommended distance from a UHD screen. ...For best visual experience. ...I simply gave an example; an assumption. 
Personally I would respect my vision first before UHD picture; so ten feet or so from a 105" screen size for me. ...In true UHD reality.



Star56 said:


> While I find some folks sitting distances to be absurdly close, there is not a shred of peer-reviewed evidence to support your nonsense about damaged eyesight.


I don't know if there were serious researches about UHD calibrated TVs and distances from them with real people's eyes for extended period of time; say six hours a day, six days a week and three hundred days a year. 
...People sitting say five feet from a 90" UHD professionally calibrated OLED curved panel TV, and with perfect room's Kelvin light...meaning very low ambiance light, similar to a properly lit professional IMAX theater. 

And then vary the time each day, by increasing it to twelve hours a day. ...And the other direction; three hours every day, six times a week, every week for a year.

My guess; nothing "nonsense" about what I just extrapolated/posted. ...Reality sinks in when science @ the sevice of human health comes to equilibrium.
I did not post a fact just my own personal opinion, and for me my opinion is totally making good pure logical sense. 

Let's find out about them serious true researches on how our eyesight might be affected from the variables I just enumerated; then we'll "see" if my *opinion* makes sense or not. Nevertheless, my opinion is valid, right or wrong...it's just an opinion...and it's mine...and I have full respect towards my opinion...I took the time for posting it by analyzing several aspects, and from the experience I posted before regarding my laptop, my android phone, and my 3D plasma TV. ...My eyes are mine, I'm used with them, and I know they hurt and feel much more tired than before when normal life and screens were part of better/smarter interaction with technological visual electronics. 

Again, nothing "nonsense" about my well calculated opinion. ...And like you just said yourself; "absurdly close". ..."Some folks sitting distances".


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## dnoonie

Scott Wilkinson said:


> Yep, that will be in my next top 10 list about the visual environment.


Awesome! I'm prepping my theater room for painting. Will you address wall color at all...of course the color and lightness surrounding the screen can be changed by the color of room treatment too. 

Cheers,


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## NorthSky

Star56 said:


> While I find some folks sitting distances to be absurdly close, there is not a shred of peer-reviewed evidence to support your nonsense about damaged eyesight.


I'm just curious; why did you put a "mad" emoticon? ...What are you mad @, ...my nonsense on the possible affectation of our eyesight when sitting closer for few hours a day from our screens? 

Headaches, sour eyes, red eyes, tired eyes, stressed eyes, ...all brain affecting...I believe. 

It's only a forum on the Internet with respectable members having respectable opinion. ...Nothing to be mad about.


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## hk2000

I've been reading A/V magazines, websites and blogs for many many years, I've never seen the viewing distance given in relation to screen _height_- I've always seen it as a ratio of screen width- as far as I can recall (can't find it right now) should be 1.5 times the screen width for HD. I don't know if the author got mixed up, or is this something new?


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## wuther

Scott Wilkinson said:


> 6. The other way for a 16:9 projector to fill a wide screen with a widescreen image is to use an anamorphic lens, which optically stretches the image horizontally while the projector electronically upscales the image vertically. For 16:9 content, the anamorphic lens can be moved out of the way, or in the case of a fixed lens, the projector can electronically scale the image to the correct aspect ratio. This approach is more expensive than zooming, but it uses all the projector's pixels, giving the image more resolution and making it brighter.


Misleading, that may well utilize the projection but the image resolution is determined by the source.


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## RLBURNSIDE

fierce_gt said:


> i've always had a 'philosophical' issue with this reasoning.
> 
> i'm a believer that resolution is really about the SOURCE and not how you manipulate it. just like watching dvd's on my 1080p tv is nowhere near the same as a true 1080p source, the minor upscaling done when using an a-lens is at best insignificant.
> 
> sure there's technically more pixels displayed, but there's not going to be more detail in the image. and i'd argue that since it's no longer a 1:1 pixel mapping, you're probably getting less. kind of like how 720p content actually looks better on 720p displays than 1080p ones.
> 
> what we really need(ed) was for UHD to be a wider format. i'd love to have native 2.35:1 displays/projectors with a source to match that. now that i've experienced CIH, it's what i want for everything. the director can decide how wide the field of view is, but i want to decide on the height of the screen as that's how i perceive 'size'.


I'm pretty sure the 21:9 flag that's part of HDMI 2.0 spec means that your UHD Bluray player can load up a 3840x1620 letterbox movie, and send only the non-black area over the wire so as to not waste bandwidth. There are 2.37:1 native monitors out there, usually 2560x1080 or 3440x1440 or so. 

Eventually they will probably all be 3840x1620 so that they can do 1:1 pixel mapping with UHD Blurays. 

The good thing about using an anamorphic lens with a 1080p projector, is that you can actually get those extra 280 vertical pixels with real information, if you can get a UHD movie over the wire to a 1080p PJ. You just take the 3840x1620 and let your PC squeeze it down to 1920x1080 anamorphic. Then your Scope movie will be really sharp. Of course you'll have to strip HDCP out because older projectors don't have the HDCP 2.2 to even accept a UHD Bluray source. I wonder if UHD Bluray players have this already in mind, like what happens when you want to play one on an older TV? Does it just say, "no?" Or does it downgrade the image to 1080p and let you run it over the older HDCP. If it doesn't, that's probably going to p*ss a heck of a lot of people off. 

The other dumb thing is that you can't even stream UHD streams on Netflix to a PC. I hope that changes, because then anamorphic projector users like myself could easily select a 2560x1080 desktop resolution with GPU scaling it back to 1920x1080 (anamorphic), and then you go to netflix and simply let the browser scale 3840x1620 movies down to 2560x1080 and then your GPU scales that down to 1920x1080 anamorphic. Your projector gets that and is very happy indeed  Also a side benefit is that FHD displays UHD with baked in 420 chroma subsampling as if it had none, in other words, the process of down-rez from 3840x1620 to 1080p means the 1080p is actually 444. Or close enough even if you do the anamorphic trick I mentioned.

Are there are streaming services that let you stream UHD video to a PC? I wonder if the HDCP 2.2 thing even comes up in that case. Is it stripped at the source? or is it still there? I'll have to look into that. Well, there's always Netflix rips if they don't want my money.


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## Red99

NorthSky said:


> I wonder how many people sit 4.4 feet from a 70" UHD TV? ...Can the brightness of the screen affect your eyes over time?
> 
> For example; I sit 18 inches from my 15" screen laptop, and I know that my eyes get tired over time.
> 
> *Back in the 50s-60s they were telling us to not sit close to our tube TVs; remember...our parents were telling us while playing on the carpet floor of the living room?
> And I remember the couch being about 12 feet from a 25" tube cathode TV. *
> 
> Today we have smart phones with a 6-7" screen size or a tablet with a 10-12" screen size and we sit about 6 inches from it...from the recommendations we should sit much closer.
> The screen brightness of our cell phones is getting right inside our eye's retinas and the radio micro-waves right in our brain.
> I'm sure all for the best, as compared to the 50s.
> 
> Now UHD is here, and even in our laptops (12 to 17" screen sizes), and OLED and LED in the 55 to 75" sizes and we can sit only few inches from them for best imprint on our eyes...details.
> 
> I'm invited to my neighbor's house to watch a UHD movie on Blu-ray ('Fury Road: Max Unchained'); we sit down, the screen is 105" diagonal, and our chairs are 6.6 feet from it.
> ...Times they are a changin'.


I remember that too, and I knew it had something to do with the CRT displays. So I googled and found where this all started at. 

_There was actually a very brief period of time where sitting close to the TV could damage your eyes, assuming you owned a General Electric TV in the 1960s. Specifically, in 1967, General Electric informed the public that many of their color televisions were emitting excessive x-rays due to a “factory error”. GE fixed this problem by putting a leaded glass shield around the tubes. __Health officials at the time estimated that the amount of radiation being given off by these defective TVs was about 10 to 100,000 times higher than the rate considered acceptable. They recommended, if you owned one of these TVs, not to sit too close. As long as you were a few feet away and didn’t watch TV for more than an hour at a time or so at this close range, you were problem fine. General Electric of course recalled all these TV’s and fixed the problem, so the issue went away._


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## NorthSky

We were all born with a pair of natural eyes. ...Light and darkness are part of our planet's solar and lunar system.

Looking @ a bright screen (iPhone, android, tablet, laptop, PC's screen, plasma TV, LCD LED TV, OLED TV, images projected on a big screen, ...), several hours a day (say more than three), and sitting close to those screen displays, ...how do we know for sure the effects they all have on our eyes? ...It certainly isn't part of the normal/natural human evolution/condition, and they cannot keep up with new scientific research with all today's newest technologies, because it takes time (years) to have conclusive results. 

So, what do we do? ...We use common sense, and awareness of our eye's changes from our new electronic environment.

Yes, seating distance recommendations are only purely for field-of-view and pixel density and detailed images, and not for health hazard issues.
Three times (for HD) the screen's height is 1.5 times the screen's diagonal; just another equation to measure/calculate the exact same thing.

With UHD, it's now 1.5 times the screen's height, or 0.75 times the screen's diagonal. 

What does it do to our eye's natural health? Very simple; try it for few hours every day, six days a week, and for a full year.
But first get measurements of your eyes (health condition) before you perform the test, and then later on, after a year under the test.
It has to be consistent; number of hours and days and with the UHD best recommended seating distance (1.5 times the screen's height), to be scientifically objective.

But my best guess? ...And before you can terminate the test (a year); your eyes and your head will tell you in advance...say just few weeks. 

This is my opinion, not a fact. And I invite doctors, eye's experts, scientists, TV people, ...to discuss my theory.


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## Gary Lightfoot

IanR said:


> It seems to me that we're mixing up the rationales for distance. In the past, the ratios have been different depending on resolution of the content/display .. ie. SD vs HD. But I thought the 40 degree recommendation (or 36) was largely determined by our field of vision and/or by the limits of 'immersion'. If that's the case, then the optimum distance should be independent of the resolution. With UHD and the 1.5 SH recommendation, I haven't done the math but it seems to me that you'd be violating the 36/40 degree viewing angle recommendation.


I'm inclined to agree - there are THX documents that show that even 70mm movies should still be shown in a CIH set up, so even though 70mm is effectively a higher res image, THX aren't suggesting that it should be shown bigger/taller or we move our seats closer, so preserving the horizontal viewing angles they recommend (40 for 16:9, 52 for scope, 36 is their recommended viewing angle for the back row)

Sony appear to be suggesting we sit closer because their 4k images require closer seating distances to better resolve the increased resolution, but then that can compromise viewing angles and puts vertical viewing angles at the recommended maximum which could be problematic for non IMAX type movies and prolonged viewing.

Gary


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## CinemaAndy

DrMichael said:


> These are interesting points. There is a lot of research being done on Blue Light that is emitted by smart phones, tablets and televisions. It is very close to UV light on the wavelength spectrum and is being concluded that it causes eye strain and possible negative effects to the health of the eyes.
> As far as viewing distance there is a point at which eye strain will be an issue. Basically anything closer than 20 ft will demand the eyes to consistently focus to keep the image clear. This will bring about eye strain over time. In my professional opinion I always suggest sitting at least 8 ft away from the television.


Wasn't that the specified distance from the old CRT tube TV's as well?


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## Gary Lightfoot

fierce_gt said:


> i've always had a 'philosophical' issue with this reasoning.
> 
> i'm a believer that resolution is really about the SOURCE and not how you manipulate it. just like watching dvd's on my 1080p tv is nowhere near the same as a true 1080p source, the minor upscaling done when using an a-lens is at best insignificant.
> 
> sure there's technically more pixels displayed, but there's not going to be more detail in the image. and i'd argue that since it's no longer a 1:1 pixel mapping, you're probably getting less. kind of like how 720p content actually looks better on 720p displays than 1080p ones.
> 
> what we really need(ed) was for UHD to be a wider format. i'd love to have native 2.35:1 displays/projectors with a source to match that. now that i've experienced CIH, it's what i want for everything. the director can decide how wide the field of view is, but i want to decide on the height of the screen as that's how i perceive 'size'.


Depending on how close you sit to a projected 2.35 image, you will often find that with a good anamorphic lens, the interpolated image will look less chunky and sharper than the zoomed image. That's because when you zoom x 33% you are effectively moving your seats closer by 33% so the pixels are that much larger and more visible.

Gary


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## Gary Lightfoot

Orbitron said:


> Shouldn't there be one more measurement - the relationship of the vertical position of the screen/vertical head angle? A ceiling mounted screen that lowers, you are looking slightly upward, a fixed screen positioned where you are looking straight ahead.


It's recommended that you should have no more than a 15 degree vertical viewing angle to the top of the screen and a maximum of 35.

Gary


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## NorthSky

♦ www.rtings.com/info/television-size-to-distance-relationship
♦ https://en.wikipedia.org/wiki/Optimum_HDTV_viewing_distance

♥ http://myhometheater.homestead.com/viewingdistancecalculator.html

♦ www.hdtvtest.co.uk/Article/How-Far-Should-I-Sit.php
♦ www.cnet.com/news/how-big-a-tv-should-i-buy/

♦ www.thx.com/consumer/home-entertainment/home-theater/hdtv-set-up/
♦ www.crutchfield.com/S-fOMBcz2vIhb/learn/learningcenter/home/TV_placement.html


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## Scott Wilkinson

Orbitron said:


> Shouldn't there be one more measurement - the relationship of the vertical position of the screen/vertical head angle? A ceiling mounted screen that lowers, you are looking slightly upward, a fixed screen positioned where you are looking straight ahead.


That's coming in the next list about viewing environment.


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## IanR

Gary Lightfoot said:


> It's recommended that you should have no more than a 15 degree vertical viewing angle to the top of the screen and a maximum of 35.
> Gary


I'm having trouble with your comments "no more than" in the same sentence as "maximum". Did you mean a minimum of 15 and maximum of 35?


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## Scott Wilkinson

dnoonie said:


> Awesome! I'm prepping my theater room for painting. Will you address wall color at all...of course the color and lightness surrounding the screen can be changed by the color of room treatment too.
> 
> Cheers,


Yep, wall color will definitely be included in the viewing-environment list.


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## Gary Lightfoot

IanR said:


> I'm having trouble with your comments "no more than" in the same sentence as "maximum". Did you mean a minimum of 15 and maximum of 35?


I don't know if there is a minimum (I'm guessing not as it's easier to look down than up), but THXs site may be clearer:

http://www.thx.com/consumer/home-entertainment/home-theater/hdtv-set-up/

Although they (and Dobly and SMPTE IIRC) suggest no more than 15 degrees, it's also said that the max vertical should be 35, which suggests that after 15 degrees viewing fatigue from looking up too much for long periods can start to be problematic, with greater than 35 degrees probably being guaranteed tiring. THX suggest that 35 degrees be the max vertical viewing angle from the front row:

http://www.film-tech.com/warehouse/manuals/TAPGUIDELINES.pdf

Gary


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## fierce_gt

Gary Lightfoot said:


> Depending on how close you sit to a projected 2.35 image, you will often find that with a good anamorphic lens, the interpolated image will look less chunky and sharper than the zoomed image. That's because when you zoom x 33% you are effectively moving your seats closer by 33% so the pixels are that much larger and more visible.
> 
> Gary


i have not experienced this, personally. but if i'm going to play devil's advocate, i'd say this is another reason why a native 'scope' format would be desirable. it'd be nice if the scope movie had the same vertical resolution as a 16:9 one.


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## Gary Lightfoot

fierce_gt said:


> i have not experienced this, personally. but if i'm going to play devil's advocate, i'd say this is another reason why a native 'scope' format would be desirable. it'd be nice if the scope movie had the same vertical resolution as a 16:9 one.



That's my experience, and those of others here.

I completely agree that a native scope format is desirable so that movies can be shown correctly in relation to each other (CIH). Nobody in the industry appears to like CIW but when it comes down to cost, that is always the bottom line at the multiplex. If they can save $10,000 on an anamorphic lens and have more 16:9 screens they can get more punters in to make more money, that's the route they're going to take. Presentation is no longer part of the equation (many theatres don't even have masking now, and aren't bothered that the main feature may even be smaller than the preshow adverts etc), and many people are now no longer aware that scope should be the same height and wider than flat. They hate the black bars on their tv and now get them at the cinema so hate the ratio because of it. They don't know it's presented the wrong way round.

Unfortunately, it doesn't look like scope/21:9 is supported in the UHD BD format, so unlikely to be taken up by manufacturers. It didn't do well when Philips and Visio made 21:9 tvs, so may have already died a death for the consumer.

Gary


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## mtbdudex

I find this visual guide the easiest way to show immersive viewing for a HT vs just "viewing" in a typical family room setup.

For mine, my 1st row is at 10ft 6" from my 130" diag scope screen, it's the money viewing row.....


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## p5browne

Should the sitting distance be different for someone watching one episode of a series, versus a binge watcher who watches the whole series at one sitting?


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## umeng2002

I do most of critical viewing on my calibrated PC monitor. My next monitor will definitely be 21:9... maybe curved since you sit very close. If 21:9 TVs are affordable in the near future, I'll probably go that route.


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## mo949

Shifting aspect ratios will never look right on 21:9 screens.


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## Soulburner

I find it uncomfortable to sit closer than 8 feet from my 65" screen. That was true of my DLP and my plasma. When I had to live with a 7 foot distance for a while I always wanted to push my head back into the seat to get farther away. It just was not fun.

Now that I'm at 9 feet, it's perfect.

The resolution doesn't matter for this. It's how much of your field of view is going to be consumed and whether your visual system is comfortable tracking that large of an area. I think that's going to vary from person to person.


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## Gary Lightfoot

mtbdudex said:


> I find this visual guide the easiest way to show immersive viewing for a HT vs just "viewing" in a typical family room setup.


I agree - it's a great guide and certainly makes things visually a lot easier to understand.

Here's the same diagram I updated (with Erik Garci's permission) to include THXs optimal seating distance recommendation. I've also added a photo of a page from Speaker Builder Magazine which has an interview with Tomlinson Holman (then) of THX back in 1990 which covers some of the this.

Gary


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## Gary Lightfoot

p5browne said:


> Should the sitting distance be different for someone watching one episode of a series, versus a binge watcher who watches the whole series at one sitting?


All the seating distance guidelines are just that - guidelines and recommendations, so you can sit where you like, but if immersion is important to you, then closer is better provided the image quality is acceptable (low bitrate SD may not be so good for example), and as long as you follow the guidelines about vertical viewing angles etc.

Provided you're within the guidelines, which are there for prolonged viewing in a movie theatre (and in the home as well now), you should be fine for both short and long term viewing.

Gary


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## Gary Lightfoot

mo949 said:


> Shifting aspect ratios will never look right on 21:9 screens.


I'm not sure I understand you correctly, but Constant Image Height has been around since 1953, and works really well with just side curtains masking in for each smaller ratio, so 2.35 would be the widest format with all others being shown the same height and less wide (see the image I posted earlier). 

16:9 screens show scope presentations smaller instead of larger and is the wrong way round. It's certainly not how or why the scope format was designed in the first place.

Gary


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## RLBURNSIDE

granroth said:


> Honestly, I look at the recommended distances as appropriate for watching TV, not movies. I want to be fully immersed into a film and sitting 3x the height puts me squarely in my second row. It's not bad to be there, but it's not even close to being as immersive as my front row.
> 
> The heuristic that works for me is to sit close enough that any closer will make you feel nauseous in quick motion scenes. I find that to be somewhat closer to 2x the height.


+1

My couch is usually about 12-14 feet away from my 10-foot wide image (138 inch diagonal). It's really big and immersive but not "nosebleed section at the theaters" by any means.

On the topic of nosebleed, what I find odd is how many people mount their TVs over their head. That I cannot understand. You should have the center of the screen at eye level, or around there plus or minus. That's not really possible for most projector setups, but it definitely is for TVs. I just don't get why so many people like to look up and crank their necks that high. Does not compute.


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## CosmoNut

I really wonder about the "standard" calculations for measuring seating distance from a UHD display. I've read enough people's comments here about how their view of 1080p changed drastically once they owned a UHD television for a while. They can see the pixels.

For me, there's a certain je ne sais quoi when I look at UHD displays in the store versus 1080p. I know that I can't see the individual pixels on either, but something about the UHD sets *feels* sharper, more crisp, and more realistic. Maybe it's just confirmation bias, but I have a feeling I'd be able to tell the difference between native content on a 1080p set vs. UHD set, all else being equal.


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## mo949

Gary Lightfoot said:


> I'm not sure I understand you correctly, but Constant Image Height has been around since 1953, and works really well with just side curtains masking in for each smaller ratio, so 2.35 would be the widest format with all others being shown the same height and less wide (see the image I posted earlier).
> 
> 16:9 screens show scope presentations smaller instead of larger and is the wrong way round. It's certainly not how or why the scope format was designed in the first place.
> 
> Gary


Gary, things have changed a bit since 1953 and now we have many Directors playing around with shifting aspect ratios in their movies, such as Interstellar, to develop a sense of scale/largeness. In interstellar you notice that many of the outdoor/cinematic scenes are in 16:9 format , whereas the character/dialogue scenes are 21:9.

On a 21:9 (CIH) TV screen this would reverse the intent of the director. The "Large" scenes would appear smaller.


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## Gary Lightfoot

mo949 said:


> Gary, things have changed a bit since 1953 and now we have many Directors playing around with shifting aspect ratios in their movies, such as Interstellar, to develop a sense of scale/largeness. In interstellar you notice that many of the outdoor/cinematic scenes are in 16:9 format , whereas the character/dialogue scenes are 21:9.
> 
> On a 21:9 (CIH) TV screen this would reverse the intent of the director. The "Large" scenes would appear smaller.


And how many of these AR changing movies are there right now?

CIH has been around since 53 and is still current, so it's not like it's an old method that's no longer in use, and IMAX requires a very different install. Why compromise all the many thousands of scope movies for maybe a dozen AR changing movies that may be just a fad or remain very much a minority?

Gary


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## mo949

I stated that shifting aspect ratios are not displayed properly on a 21:9 screen and you got confused. You didn't say "how many titles are like that" then. (and btw, many of the greatest blockbusters that come out in these last few years have employed them). You are entitled to your preferences though, I was just helping you understand the facts since you were confused and asked.

I'm not compromising as much as I would with a 21:9 TV. In fact a 21:9 tv is also a compromise in another area for home users, namely screen real estate. We all want to fit as much screen in that we can, right?

In most homes the constraint on space is usually limited more by width than by height. If you go with a 21:9 TV in such a space, you've essentially given up potential screen real estate you otherwise would have been able to fit in the same space with a 16:9 tv - and 2.33 content would still be the exact same size (1.78 would be bigger - and there's not many complaints about that last I checked). At the other extreme is the 4:3 Size, but at that point you'd be about equally limited in both height and width and have issues with center channel placement (unless you use a PJ and an acoustically transparent screen).


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## NorthSky

Wikipedia mentioned 4 times the height of your display for HDTV. ...So for a 120" screen (diagonal) that would be 20 feet distance from it?


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## Soulburner

NorthSky said:


> Wikipedia mentioned 4 times the height of your display for HDTV. ...So for a 120" screen (diagonal) that would be 20 feet distance from it?


What was their source? Since Wikipedia isn't making their recommendation themselves. 3.0-3.5x is my sweet spot for 65". Not too far to lose the effect of a large screen, and not too close to feel nauseas.

4x puts me at 10.8 feet, which is too far.


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## jimv1983

I can't imagine there are a lot of people out there that will sit closer to a UHD screen than a 1080p screen just because they can do it and not see pixelation. In my experience people tend to choose viewing distances based on room layout and then getting a TV that fills the field of vision and that distance. I can't imagine people getting a large screen just because UHD will allow it without a visible loss in resolution. The recommendation for a 70" UHD screen is 4.4 feet? Who the heck would even want to sit that close to a TV that large? The thought of that eye strain makes me cringe.


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## Gary Lightfoot

mo949 said:


> I stated that shifting aspect ratios are not displayed properly on a 21:9 screen and you got confused. You didn't say "how many titles are like that" then. (and btw, many of the greatest blockbusters that come out in these last few years have employed them). You are entitled to your preferences though, I was just helping you understand the facts since you were confused and asked.


You're confusing a pertinent question with a lack of understanding. I merely asked because those IMAX style movies with changing ARs are few and far between, so hardly worth designing a home theatre around when there are a greater amount of scope presentations out there to be considered. You'll probably find that there are more scope 'blockbusters' than there have been changing AR 'blockbusters'.



mo949 said:


> I'm not compromising as much as I would with a 21:9 TV. In fact a 21:9 tv is also a compromise in another area for home users, namely screen real estate. We all want to fit as much screen in that we can, right?




Wrong actually. It's a newbie mistake to go for the largest screen that fits their wall without considering viewing angles and seating distance and ignoring or forgetting about scope. If you read the THX article I posted earlier, you will see how movies should be presented correctly if doing it right is important to you.



mo949 said:


> In most homes the constraint on space is usually limited more by width than by height. If you go with a 21:9 TV in such a space, you've essentially given up potential screen real estate you otherwise would have been able to fit in the same space with a 16:9 tv - and 2.33 content would still be the exact same size (1.78 would be bigger - and there's not many complaints about that last I checked). At the other extreme is the 4:3 Size, but at that point you'd be about equally limited in both height and width and have issues with center channel placement (unless you use a PJ and an acoustically transparent screen).


The above is a common mistake when you don't think about viewing angles, seating distance or ideal presentation for the majority of movies out there. Scope should be the widest largest format other than IMAX.

Stop thinking about screen real estate, and think more about retina real estate. Because we have binocular vision, we see more horizontally than vertically, so we are limited vertically and that's why seating distance is often referred to with respect to screen height, and why there is a vertical viewing angle recommendation of 15 degrees. That's considerably less than the 45 or 52 degrees commonly recommended for horizontal viewing angles (for scope). Screen height works for all aspect ratios, whereas width will be confusing without knowing the screens aspect ratio.

If you go for the widest 2.35 screen you can fit, you then place your seating at the correct distance to achieve your preferred viewing angles. If you take THXs recommended angles of around 40 degrees for 16:9, and 52 degrees for scope, you will find that your seat will be approx 2.4 x the image hight for both formats with a 2.35 screen when viewed from the same seat.

As for those people who don't complain about 16:9 screens, they are usually the ones who complain about the black bars when viewing scope movies.

If you think just purely in screen size and the largest screen you can fit on your wall, you would end up with a 4:3 screen and the largest format movie (scope) being shown as the smallest and vice versa.

If you do the same with a 16:9 screen, you will probably place your seats where that looks fine to you, and then scope is compromised. But if you take that viewing angle/seating distance, and apply it to a 2.35 screen, you will move the seats forward to retain the same viewing angles, 16:9 looks as large as before (same size image on your retina so visually not compromised), and now scope presentations are wider and more immersive, just as designed.

If you do it correctly, no format is compromised on a 2.35 screen.

If the few IMAX style changing AR movies are important to you, you could fit a 16:9 screen, but mask it down to scope, and place your seating accordingly (using the scope screen height as your working screen height for seating arrangements). Then you have designed primarily for scope and will see normal 16:9 movies the same height and less wide than scope movies, just as they should be. When you want to watch one of the changing AR movies, you can remove the top and bottom masking to reveal the full 16:9 screen, and get an IMAX style presentation. Ideally a 4k projector would be the best choice for that though.

Gary


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## NorthSky

Soulburner said:


> What was their source? Since Wikipedia isn't making her recommendation themselves. 3.0-3.5x is my sweet spot for 65". Not too far to lose the effect of a large screen, and not too close to feel nauseas.
> 
> 4x puts me at 10.8 feet, which is too far.


♦ https://en.wikipedia.org/wiki/Display_size

* A 65" diagonal display (HD): Between 8 and 9 feet viewing distance, I'd say. ♠ https://www.avsforum.com/POSTs



jimv1983 said:


> I can't imagine there are a lot of people out there that will sit closer to a UHD screen than a 1080p screen just because they can do it and not see pixelation. In my experience people tend to choose viewing distances based on room layout and then getting a TV that fills the field of vision and that distance. I can't imagine people getting a large screen just because UHD will allow it without a visible loss in resolution. The recommendation for a 70" UHD screen is 4.4 feet? Who the heck would even want to sit that close to a TV that large? The thought of that eye strain makes me cringe.


♦ I agree, 5 to 10 feet would be more reasonable. ...Right in the middle would be 7.5 feet (for UHD - 70" screen diagonal). 
...Or make that 4.4 feet times two, equals 8.8 feet. ...Now we're talking, for 70" diag. UHD (true 4K content).


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## mo949

Gary, your uncertain understanding and this discussion began around the rare and possibly extinct 21:9 TVs and a very simple statement I made. Remember, I said home user and *21:9 TV* in a normal home application in my follow up. Reality is most of us are constrained by space and layouts in our typical home environments and would love to be able to enjoy more screen real estate. The reality of constrained-by-widths is that it cannot get any wider in your room (in mine I would have no place for the speakers to sit if any wider). Its pretty simple to see that the 16:9 would be preferable in that case, as it most certainly is to me. The fact that I get to enjoy some of the best videophile 65/70mm Imax presentations ever, is just icing on the cake for me. As for 4:3, I addressed that in my previous post and pointed out why your assertion that 'they' would use those instead is ridiculous in the real world of choosing the ideal compromise.

Our Retina's and viewing are not being compromised by adding a 16:9 into that spot rather than a 21:9 - it is after all only a little over half the vertical distance of a standard height room we can even use since you wouldn't be able to see the portion of the screen touching the floor if you installed it that way and I doubt you'd want the screen touching the ceiling either. The extra vertical 1-2ft of visual nirvana we add to our setups our retina's can handle. Its misleading at best to suggest otherwise and try and use arguments geared toward the actual 'big' screens into our typical ~14x16x9 type living rooms; I have plenty of 'Retina Real Estate' to spare, but I don't have plenty of wall space.

Another Reality Check: UHD is actually halving the recommended seating distance based on screen height, which will result in far more extreme vertical angles than merely putting a 16:9 TV in a spot rather than a 21:9 one as we've preferred to do in our homes so far.

As to your suggestion to 'mask' a 16:9 television, thankfully there's no need to mask a 16:9 Oled television since the 'black bars' will blend into the darkness completely.


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## stef2

What a strange top ten...strange or useless, but still, a list of ten random items, in no particular order.


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## fierce_gt

Gary Lightfoot said:


> That's my experience, and those of others here.
> 
> I completely agree that a native scope format is desirable so that movies can be shown correctly in relation to each other (CIH). Nobody in the industry appears to like CIW but when it comes down to cost, that is always the bottom line at the multiplex. If they can save $10,000 on an anamorphic lens and have more 16:9 screens they can get more punters in to make more money, that's the route they're going to take. Presentation is no longer part of the equation (many theatres don't even have masking now, and aren't bothered that the main feature may even be smaller than the preshow adverts etc), and many people are now no longer aware that scope should be the same height and wider than flat. They hate the black bars on their tv and now get them at the cinema so hate the ratio because of it. They don't know it's presented the wrong way round.
> 
> Unfortunately, it doesn't look like scope/21:9 is supported in the UHD BD format, so unlikely to be taken up by manufacturers. It didn't do well when Philips and Visio made 21:9 tvs, so may have already died a death for the consumer.
> 
> Gary


i always thought it was weird that'd we'd go from movies being mostly 1.85:1 and then that progressed towards a 'larger' 2.35:1 format(assuming the same height and wider screen), then imax comes along and convinces ppl that their screen is 'bigger' because it has extra height and the same width, but it's basically the same 1.85:1 screen format(i know they made improvements in the film, and that was really the difference, but that no longer really applies in the digital age).

all i know is that i've reached a limit to how tall my screen can be for me to enjoy it. watching 16:9 stuff on the 120" screen is overwhelming, and unpleasant. watching scope movies on that same screen is awesome. i now use a 100" 16:9 screen for that format. it's roughly the same height, and it feels like it's just as big.

i think we're just stuck with 16:9 right now. a scope format won't be popular unless both the source and the display match. UHD would have been an interesting time to try it. i would actually have preferred a display that kept the 1920x1080 resolution for 16:9 content(100% backwards compatible) but added horizontal resolution for a scope format. i just really don't like scaling.


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## mo949

Imax film is actually larger (I'm going to clarify I said 'film' not 'screen size' here). I'm not 100% certain on this next bit, but I seem to remember that if you were to matte/mask Imax film to a 21:9 AR it would be much larger (more information/detail) than 35mm @ 21:9. When Imax get's displayed 'open matte' or even just less 'matted' (1.85) it is still displaying a richer picture than plain old 35mm. This is why Imax portions of the disc are so much more visibly rich than the 35mm parts, even when converted to 1080p, more appropriate to think of it as larger, and why it gets used to display a larger picture during those scenes. Better source, better end product still - the difference in film used is a big difference.


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## Soulburner

mo949 said:


> Another Reality Check: UHD is actually halving the recommended seating distance based on screen height, which will result in far more extreme vertical angles than merely putting a 16:9 TV in a spot rather than a 21:9 one as we've preferred to do in our homes so far.


I agree. Viewing distance should be chosen based on field of view, not resolution.


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## Gary Lightfoot

mo949 said:


> Gary, your uncertain understanding and this discussion began around the rare and possibly extinct 21:9 TVs and a very simple statement I made. Remember, I said home user and *21:9 TV* in a normal home application in my follow up. Reality is most of us are constrained by space and layouts in our typical home environments and would love to be able to enjoy more screen real estate. The reality of constrained-by-widths is that it cannot get any wider in your room (in mine I would have no place for the speakers to sit if any wider). Its pretty simple to see that the 16:9 would be preferable in that case, as it most certainly is to me. The fact that I get to enjoy some of the best videophile 65/70mm Imax presentations ever, is just icing on the cake for me. As for 4:3, I addressed that in my previous post and pointed out why your assertion that 'they' would use those instead is ridiculous in the real world of choosing the ideal compromise.
> 
> Our Retina's and viewing are not being compromised by adding a 16:9 into that spot rather than a 21:9 - it is after all only a little over half the vertical distance of a standard height room we can even use since you wouldn't be able to see the portion of the screen touching the floor if you installed it that way and I doubt you'd want the screen touching the ceiling either. The extra vertical 1-2ft of visual nirvana we add to our setups our retina's can handle. Its misleading at best to suggest otherwise and try and use arguments geared toward the actual 'big' screens into our typical ~14x16x9 type living rooms; I have plenty of 'Retina Real Estate' to spare, but I don't have plenty of wall space.


You've clearly missed the point about seating distance and viewing angles (both horizontal and vertical) despite my best attempts to cover it (and it being part of this thread), yet you claim I've an uncertain understanding. There's even a THX article with a picture to help you. If I'm confused, so are Dolby, THX, SMPTE etc. I'm glad I'm in good company. 



mo949 said:


> Another Reality Check: UHD is actually halving the recommended seating distance based on screen height, which will result in far more extreme vertical angles than merely putting a 16:9 TV in a spot rather than a 21:9 one as we've preferred to do in our homes so far.
> 
> As to your suggestion to 'mask' a 16:9 television, thankfully there's no need to mask a 16:9 Oled television since the 'black bars' will blend into the darkness completely.


I've covered UHD/4K and Sonys recommendation of being sat at 1.5 x SH which gives around 35 degrees vertical viewing angles when viewed from the center of the screen. That's quite extreme. How would you approach that at home to achieve a comfortable viewing angle for normal non IMAX 16:9 presentations? 

I was obviously talking about big screens and not tv. I prefer watching movies on a projected set up rather than a small tv, but the same seating distances and viewing angles apply except for very small tvs for obvious reasons. Your reality is clearly very different to mine. 

Gary


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## mo949

Soulburner said:


> I agree. Viewing distance should be chosen based on field of view, not resolution.


Since I think its more relevant there. I replied to you here: http://www.avsforum.com/forum/92-co...iewing-distance-relative-screen-height-2.html


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## Orbitron

To Scott's point #4 - many projector owners get a 2.39:1 or 2.35:1 screen so that widescreen movies fill the screen without SIGNIFICANT black bars. Not to take issue but the reason I went with a 2.35:1 screen - NO black bars or screen borders.


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## jimv1983

NorthSky said:


> I agree, 5 to 10 feet would be more reasonable. ...Right in the middle would be 7.5 feet (for UHD - 70" screen diagonal).
> ...Or make that 4.4 feet times two, equals 8.8 feet. ...Now we're talking, for 70" diag. UHD (true 4K content).


For a 70" screen I would sit no closer than 12 feet and at that distance UHD isn't really noticeably better than 1080p.


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## jimv1983

Soulburner said:


> I agree. Viewing distance should be chosen based on field of view, not resolution.


I agree as well. Fill the center of my field of view. Anything bigger than than isn't appealing at all.


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## maxreactance

p5browne said:


> Black Bars are fine, as long as they just that - BLACK!


No, they're not...I was sick of letter-boxed blu-ray 23:10 
movies the first time I saw one... 

What about the new 23:10 (or whatever) monitors they are 
selling at Fry's now (I haven't read the rest of this thread, so 
I don't know if this topic has been covered). Would I be 
able to watch a blu-ray movie in full 1080p in the original 
aspect ratio of about 23:10? I want that...more than 
4K (OK, I want the same thing in 4K too, just didn't want 
to sound too greedy all at once). 

--
maxreactance


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## mo949

Gary, I apologize, I've gotten a bit impatient with you and deleted my last post (if you saw it even) since it came off a bit snarky. I understand the articles and calculations as I've read most of them before. I think if you re-read my posts you'll find that I'm only talking about the 21:9 TV's you were originally discussing as possibly already being dead in the consumer world and attempting to explain some of the reasons they were not chosen, along with my own; And doing it without broadly attributing it to misinformed/uneducated consumers, which although is likely the case in many things Audio and Video, is also not the only reason a video/audio enthusiast would choose a 16:9 format over a 21:9 format in a home environment for their main flat panel television.



Gary Lightfoot said:


> I've covered UHD/4K and Sonys recommendation of being sat at 1.5 x SH which gives around 35 degrees vertical viewing angles when viewed from the center of the screen. That's quite extreme. How would you approach that at home to achieve a comfortable viewing angle for normal non IMAX 16:9 presentations?


If you read my reply in the other thread, you'll see I think its rubbish just like many of the new brightenss standards for home environments coming out of Dolby.


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## NorthSky

Soulburner said:


> I agree. Viewing distance should be chosen based on field of view, not resolution.





jimv1983 said:


> I agree as well. Fill the center of my field of view. Anything bigger than than isn't appealing at all.


What is the best "field of view"...for each person? ...Anything to do with our personal sight vision (20/20) and the distance between our two eyes?
...Wearing prescription glasses (shape) or not? 

The THX guys (36° - which is exactly 20% of 180°), do they take into account all variables from each different person to the next, or do they go with medical examiners, eye scientists, TV manufacturers/experts, Hollywood filmmakers, average regular people chosen @ random (from which country?), and from their own set of eyes themselves (THX regulators)? ...And what kind of material do they use; 'Gravity' on Blu-ray, or 'Interstellar' @ IMAX? 
...Or 'Mad Max: Fury Road' in 3D?


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## Gary Lightfoot

mo949 said:


> Gary, I apologize, I've gotten a bit impatient with you and deleted my last post (if you saw it even) since it came off a bit snarky. I understand the articles and calculations as I've read most of them before. I think if you re-read my posts you'll find that I'm only talking about the 21:9 TV's you were originally discussing as possibly already being dead in the consumer world and attempting to explain some of the reasons they were not chosen, along with my own; And doing it without broadly attributing it to misinformed/uneducated consumers, which although is likely the case in many things Audio and Video, is also not the only reason a video/audio enthusiast would choose a 16:9 format over a 21:9 format in a home environment for their main flat panel television.


Ah, righto.




mo949 said:


> If you read my reply in the other thread, you'll see I think its rubbish just like many of the new brightenss standards for home environments coming out of Dolby.


I think I'm probably in agreement with you there then..

Gary


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## Scott Wilkinson

Orbitron said:


> To Scott's point #4 - many projector owners get a 2.39:1 or 2.35:1 screen so that widescreen movies fill the screen without SIGNIFICANT black bars. Not to take issue but the reason I went with a 2.35:1 screen - NO black bars or screen borders.


Actually, if you display a 2.39 movie on a 2.35 screen, there will be tiny letterbox bars unless you crop or scale the image.


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## Optimus_Fine

Nothing is taller than 2.39:1, since all aspect ratios are the same height due to photographic composition.
IMAX in Hollywood movies has been used with scope composition.
When you open up the frame, you're changing the types of close-ups within the movie.
Screening hundreds of scope movies in 16:9 only to watch open matte versions of Dark Knight and Interstellar (with empty space above the heads) is inherently incorrect.


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## mo949

Optimus, I wasn't implying that we should open the matte or demand that we get versions of the film that are altered to open the matte (unless the director feels its a good idea ala James Cameron and Titanic 3D). The IMAX footage in those movies is cropped/composed down to 16:9. However, the overall movies were composed, recorded, and displayed in a format where you saw 2.39:1 footage as smaller than the IMAX 16:9 footage. As such the 16:9 footage was presented as Taller/Bigger as part of the artistic intent of the directors involved; something that you wouldn't be able to present properly on a 21:9 Television, although a projector setup could manage it with the tweaks that Gary prescribes above. I was also just pointing out that the source was 'bigger' for lack of a better word to describe the differences in the types of film used to pre-empt any notions that somehow that 16:9 footage was essentially 'zoomed'.


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## RLBURNSIDE

Orbitron said:


> To Scott's point #4 - many projector owners get a 2.39:1 or 2.35:1 screen so that widescreen movies fill the screen without SIGNIFICANT black bars. Not to take issue but the reason I went with a 2.35:1 screen - NO black bars or screen borders.


From what I understand, 2.37 : 1 is the closest AR to a 16:9 screen + anamorphic lens (1.78 * 1.333 = 2.37). That translates to 1920x810 for FHD, 2560x1080 for 21:9 native monitors, or 3840x1620 for UHD. Although many movies are apparently 1920x800, I'm not sure what the actual amount of vertical resolution the majority of scope movies use. I know Top Gun has 800. Lack of standardization is a shame. In film they didn't care much because the inherent resolution even in 35mm is around 6000 lines, which is way higher than even UHD can provide (1620 vertical lines for a scope movie).

It's probably best to zoom your lens so fill the vertical and have a tiny bit of spillage on the left and right than doing any additional vertical scaling which deteriorates sharpness slightly. Although for UHD movies I doubt anyone could tell the difference between 3840x1620 and 3840x1600 scaled to 1620 prior to projection. Although if you are doing anamorphic you have to do vertical scaling anyway so you might as well use a processor that fills your screen fully and just live with a tiny AR skew. It's highly unlikely anyone can tell the difference between 2.35 : 1, 2.37:1, or 2.4 : 1 being the final AR used to display a natively 2.4 : 1 movie.


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## Gary Lightfoot

Although film has a theoretically greater resolution, most films go via a 2k Digital Intermediate, and with bulk release prints and many runs through the gate, the quality is less than 2k by the time most of us get to see it. As a presentation medium film is not as consistent as digital.

It's also pretty sad that most DCI films are released in much the same was as Blu Ray - scope is letterboxed as the smaller format, and not may multiplexes have spent the money on an anamorphic lens (or masking). The projector imager can do a vertical stretch just like we can at home, but not many theatres seem to do that any more.

It's pretty sad really.


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## DeadEd

NorthSky said:


> Nice thread, with few important points missing. ...Are we blind?


No, your bangs are just too long.


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## Gary Lightfoot

NorthSky said:


> What is the best "field of view"...for each person? ...Anything to do with our personal sight vision (20/20) and the distance between our two eyes?
> ...Wearing prescription glasses (shape) or not?


Personal preference and visual acuity, taking into account the range of seating available in a commercial theatre to help you choose, and the recommendations from the bodies of research. Regardless of how good or bad your eyes are, when you go into a commercial theatre, you have to choose from the range of seating available to you. If you need to wear glasses to see 'normally', I would do that.



NorthSky said:


> The THX guys (36° - which is exactly 20% of 180°),


36 degrees is where they recommend the back row should be. It seems to be a common misconception that 36 is where they say you should sit.

See my earlier posts abut SMPTE recommendations.



NorthSky said:


> do they take into account all variables from each different person to the next, or do they go with medical examiners, eye scientists, TV manufacturers/experts, Hollywood filmmakers, average regular people chosen @ random (from which country?), and from their own set of eyes themselves (THX regulators)? ...And what kind of material do they use; 'Gravity' on Blu-ray, or 'Interstellar' @ IMAX?
> ...Or 'Mad Max: Fury Road' in 3D?


Although there are variations, we all see in pretty much the same way. Things like colour space in Human vision is often referred to as a 'Standard Observer' for example. So we don't need to use specific films to establish anything, just the known capability of the average persons visual system. 

Seating distances are just recommendations and we can decide for ourselves where we want to sit, but I think it's useful that people like SMPTE etc have already done the research so we don't have to. As you can see, most cinemas are built with a similar range of seating, so with that in mind, we can decide where in that range we'd like to sit at home _if_ we want a similar experience to a commercial theatre (if you just watch soaps and the news, then this thread probably isn't for you). CEDIAs white paper for home theatre (CEB23) actually suggests that you take the client to a cinema to see where they like sitting and replicate that in their viewing space if they're unsure.

It's not unusual for people to be unaware of just how close they sit when they go to the cinema, and when they see the recommendations they say that's way to close and they will be getting head movement, which isn't going to be the case with current recommendations (UHDs 1.5SH notwithstanding). 

Gary


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## NorthSky

Gary Lightfoot said:


> Personal preference and visual acuity, taking into account the range of seating available in a commercial theatre to help you choose, and the recommendations from the bodies of research. Regardless of how good or bad your eyes are, when you go into a commercial theatre, you have to choose from the range of seating available to you. If you need to wear glasses to see 'normally', I would do that.


♠ Personal preference; you just said it, and I agree. 
- If the theater is empty it's easy; we just sit where we feel like it.
- If the theater is full; we are in deep trouble.
- If the theater is half full (or half empty); we have half choice. 

@ home it's different; our seat is always available, unless the wife or one of the kids took it. Then we just take the next one to it. 



> 36 degrees is where they recommend the back row should be. It seems to be a common misconception that 36 is where they say you should sit.
> See my earlier posts abut SMPTE recommendations.


♠ THX recommends 36° (field of view) as the most immersing one. ...It's only a guide, from their extended scientific researches and with the help of other industry's experts. 
Now you say that's the back row! ...How about the front row, ...60°, or a bit more (61.8°)?

I looked @ several links and recommendations from several movie and TV organisations...it varies...from roughly a minimum of 20° to a maximum of 66.275° ...but more if inclined to, like in the front row of an IMAX theater (the true Big Size IMAX one) where you almost turn your head behind you to see what's going on! 

♦ Anyway, a good middle ground seems to be in the range of 25-50° ...and with 37.5° being dead in the middle.
Some folks @ home have a 12.5° field of view, others a 48.5° one. 

Everything is just a guide for not everyone, and preference is only what we are used to and believe so far.
We can always improve our preference by experimentation, and create our own personal guide. 
The best field of view is where each one of us feel the most comfortable with his own set of eyes, for the entire length of the movie.
It could be anywhere from zero to 360°, somewhere between.  ...Just being humorous. ,,, And in particular with 3D movies. 



> Although there are variations, we all see in pretty much the same way. Things like colour space in Human vision is often referred to as a 'Standard Observer' for example. So we don't need to use specific films to establish anything, just the known capability of the average persons visual system.
> Seating distances are just recommendations and we can decide for ourselves where we want to sit, but I think it's useful that people like SMPTE etc have already done the research so we don't have to. As you can see, most cinemas are built with a similar range of seating, so with that in mind, we can decide where in that range we'd like to sit at home _if_ we want a similar experience to a commercial theatre (if you just watch soaps and the news, then this thread probably isn't for you). CEDIAs white paper for home theatre (CEB23) actually suggests that you take the client to a cinema to see where they like sitting and replicate that in their viewing space if they're unsure.
> It's not unusual for people to be unaware of just how close they sit when they go to the cinema, and when they see the recommendations they say that's way to close and they will be getting head movement, which isn't going to be the case with current recommendations (UHDs 1.5SH notwithstanding).
> Gary


♠ Yes, I agree with you Gary.

B y the way, I only watch soap operas and CNN news on my TV, so this thread doesn't concerned me personally.  
Just kidding, I don't have cable or satellite TV for @ least the last twenty years; I only/strictly watch Blu-ray movies...no streaming no downloads no Voodoo magic. ...And I love 3D, both @ home and @ IMAX. 
I also watch music video concerts and documentaries, always on Blu-ray. I got no time to watch inferior video formats in life. 
My screen is normal (16:9), and I normally have a field of view of roughly 30°. ...I tried further away and it was too far, for me.
I tried closer, and it would be ok with a front projector (50° or so). ...And closer is also good for the bass impact, with all the subs forming a wall of sound in the front soundstage. ...And with some judicious bass EQ, of course. 

Now, curved screens, the large ones, between 70" and 240". ...Another variable to consider and expand our field of view. 

And last, in the future; ...holographic 4D movies. ...And what aspect ratio and what distance from those. ...We'll just have to live long enough to experience the brand new world of movie watching in tomorrow's future. 

But today there is no magic recipe, only movie magic.


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## NorthSky

Gary, are you related to Gordon?


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## Gary Lightfoot

NorthSky said:


> ♠ Personal preference; you just said it, and I agree.


Yes, but with the knowledge we have on avs it's a more informed preference. 



NorthSky said:


> ♠ THX recommends 36° (field of view) as the most immersing one. ...It's only a guide, from their extended scientific researches and with the help of other industry's experts.
> Now you say that's the back row! ...How a bout the front row, ...60° or more?


36 degrees has always been for the back row viewing a cope screen. It's been misquoted so many times that people think it's the most immersive place to sit, which it isn't.

THX recommend 52 degrees, 2.4 xSH as the most immersive place to sit which equates to 40 degrees for 16:9 in the same seat (2.4xSH). If you look on their website and do the calcs, that's what they are saying there for the home:

http://www.thx.com/consumer/home-entertainment/home-theater/hdtv-set-up/

The closest seating position they recommend equates to 2.4 xSH after rounding up (50" is 4.9 at 2.4SH feet but they put 5ft). The furthest is 3.68 xSH which is 36 degrees for scope when sat in the back row.

Here's a link which clearly shows 36 degrees for the back row:

http://www.thx.com/professional/cinema-certification/thx-certified-cinema-screen-placement/

Here's an older THX Theatre Alignment Program guide in pdf which also states the 36 degrees for the back row (page 10 screen image size and viewing angle distortion):

http://www.film-tech.com/warehouse/manuals/TAPGUIDELINES.pdf

I earlier posted a page of an interview with Tom Holman (of then THX) which says much the same, including the 52 degree optimum recommended seating distance for scope, along with an updated diagram that includes many recommendations from the main bodies of research (Fox, SMPTE, THX) which takes out a lot of the guesswork:

http://www.avsforum.com/forum/301-a...een-size-seating-distance-2.html#post35214362


Gary


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## Gary Lightfoot

NorthSky said:


> Gary, are you related to Gordon?


Yes, he's my sister 

Only joking, he's no relation as far as I'm aware.


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## NorthSky

Ok Gary. ...All in all.


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## freakyguy666

*Wrt aspect ratios & seating distance....*

....I echo mo949's sentiments exactly. 

I have a 14ft wide 16x9 screen in a dedicated theater. And I don't notice black bars during scope. And I have the added benefit of viewing some of the biggest blockbusters in recent history LARGER than if I had opted for a CIH Scope screen. 

Plus it's nice to watch my favorite sports in as large a screen as possible--unlike those with CIH Scope screens. 

Finally, multiple rows allows me to shift my "money seat" location depending on the AR.

Kudos to mo949!


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## Gary Lightfoot

If you move your seating depending on the AR, you're effectively running a CIH scope set up from a visual perspective despite having a CIW 16:9 screen (sit closer for scope, further back for 16:9). With a scope set up, you don't have to move your seats because the height is already as tall as you would like it (if set up correctly).

Sports usually favour larger 16:9 screens is are considered a better choice.

Gary


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## jeffs95033

A timely discussion, as I just purchased my first PJ, a JVC RS15 from a nearby upgrader.

First task at hand was to lock in what size screen to buy. I had to make sure it would look right from my rear row (2.5ft from my theater back wall) and my primary spot (5 ft forward of that), which works out to 11.5-12ft from screen. I also needed to make sure the PJ was going to throw enough light from its enclosure through a glazed portal in the back wall (19.5ft).

I believe in experimenting before committing. So I marched down to a local AV shop and rented a 10x7.5ft collapsible screen. I set my zoom to match the 10ft width and tried a couple viewing positions. What I discovered was that I prefer the same viewing angle at home as I seek when I go to the theater (imagine that!) Whenever I go to the movies, I pick a row where the screen width hits my preferred field of vision, and it's pretty consistent (yes, I often wait for, or re-watch, ~3rd week of release on a weeknight if I want a good seat). In my HT, that sweet-spot turned out to be 11.5ft = 2.0x _image_ height for 1.78 AR content (2.7x for 2.38 AR at constant-width letterbox) = 47deg horiz viewing angle. I guess I'm just a deep-immersion kind of guy.

I then tried my back row distance (16.5ft). It looked very nice, I'm sure my passengers won't complain, but it's not what I built my theater for.

Illumination was descent at low-lamp, but as I was watching Avatar for my test run, I found high-power to be absolutely addictive. I walked half the dx to the screen, took a good look around and didn't see anything that looked like jaggies. 

So I guess it's time to put in my order for a 135" 16:9. I'm real glad I did that experiment rather than following the various guidelines for the masses. To paraphrase an earlier poster, "Opinions vary", which, when you think about it, is the only assertion that is impossible to disagree with.










The Experiment
First-ever photo of Jeff's HT build... the journey has just begun.
​


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## Gary Lightfoot

Deep immersion would be 2 x SH with a scope screen 

Then you could move all your seats closer and have more room between the rear seats and back wall.

10ft wide 2.35 screen, front row 8.5ft from the screen, 2nd row 13.5ft from the screen. Give that a go and see what you think - it will mean zooming 16:9 smaller so that the height is the same as 2.35 is when 10ft wide.

Gary


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## Craig Peer

Gary Lightfoot said:


> Yes, but with the knowledge we have on avs it's a more informed preference.
> 
> 
> 
> 36 degrees has always been for the back row viewing a cope screen. It's been misquoted so many times that people think it's the most immersive place to sit, which it isn't.
> 
> THX recommend 52 degrees, 2.4 xSH as the most immersive place to sit which equates to 40 degrees for 16:9 in the same seat (2.4xSH). If you look on their website and do the calcs, that's what they are saying there for the home:
> 
> http://www.thx.com/consumer/home-entertainment/home-theater/hdtv-set-up/
> 
> *The closest seating position they recommend equates to 2.4 xSH after rounding up (50" is 4.9 at 2.4SH feet but they put 5ft). The furthest is 3.68 xSH which is 36 degrees for scope when sat in the back row.*
> 
> Here's a link which clearly shows 36 degrees for the back row:
> 
> http://www.thx.com/professional/cinema-certification/thx-certified-cinema-screen-placement/
> 
> Here's an older THX Theatre Alignment Program guide in pdf which also states the 36 degrees for the back row (page 10 screen image size and viewing angle distortion):
> 
> http://www.film-tech.com/warehouse/manuals/TAPGUIDELINES.pdf
> 
> I earlier posted a page of an interview with Tom Holman (of then THX) which says much the same, including the 52 degree optimum recommended seating distance for scope, along with an updated diagram that includes many recommendations from the main bodies of research (Fox, SMPTE, THX) which takes out a lot of the guesswork:
> 
> http://www.avsforum.com/forum/301-a...een-size-seating-distance-2.html#post35214362
> 
> 
> Gary



Good info. I'd have to say that how close one can sit also depends on the screen material and the projector. I split the difference with 2 electric screens. 2.68 screen heights for my 128" diagonal 2.35:1 StudioTek 130 G3 screen, and 2.16 screen heights for my 122" diagonal 16:9 Stewart Cima Neve. I would have liked to have gone slightly larger on the 2.35:1 screen, but a 14' throw distance makes that difficult. All in all, a good compromise though !


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## scarabaeus

RLBURNSIDE said:


> From what I understand, 2.37 : 1 is the closest AR to a 16:9 screen + anamorphic lens (1.78 * 1.333 = 2.37). That translates to 1920x810 for FHD, 2560x1080 for 21:9 native monitors, or 3840x1620 for UHD. Although many movies are apparently 1920x800, I'm not sure what the actual amount of vertical resolution the majority of scope movies use. I know Top Gun has 800. Lack of standardization is a shame. In film they didn't care much because the inherent resolution even in 35mm is around 6000 lines, which is way higher than even UHD can provide (1620 vertical lines for a scope movie).
> 
> It's probably best to zoom your lens so fill the vertical and have a tiny bit of spillage on the left and right than doing any additional vertical scaling which deteriorates sharpness slightly. Although for UHD movies I doubt anyone could tell the difference between 3840x1620 and 3840x1600 scaled to 1620 prior to projection. Although if you are doing anamorphic you have to do vertical scaling anyway so you might as well use a processor that fills your screen fully and just live with a tiny AR skew. It's highly unlikely anyone can tell the difference between 2.35 : 1, 2.37:1, or 2.4 : 1 being the final AR used to display a natively 2.4 : 1 movie.


Just to provide a few accurate numbers: You are right about the 2.37:1, it is 16:9 multiplied by 4/3 (i.e. 4:3 ^ 3, where 16:9 is 4:3 ^ 2), or *64:27*, 2.370370...:1. This is commonly referred to as "21:9", even though no video or screen in that 7:3 aspect ratio exists.

As for movie content, the last SMPTE aperture definition for 'scope on 35mm film equated to a *55:23* aspect ratio, or 2.3913...:1 aspect ratio. The DCI specification for cinemas adapted this to 2048x858 and 4096x1716 resolutions with square pixels, or 2.3869...:1, while still calling it "2.39:1". On top of that, this is often referred to as 2.4:1. Every movie since the 70's is using 2.39:1, and not 2.35:1 or 2.4:1. 2.35:1 can be found in older movies from the 50's and 60's.

For a projection screen, I would go with 64:27 instead of 2.39:1, since this will involve a simple scale or zoom by 4/3 for 16:9 projectors. There will be minor letterbox bars for 2.39:1 content, and slight cropping for old 2.35:1 movies, but that should be barely noticeable, and 2.37:1 is a good compromise.


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