# When is the screen size too big?



## Guest (Oct 17, 2011)

I've read of a few post around that sometimes people use too big of a screen. When is a screen too big? Obviously if you have to bend your neck or if you can't even see the whole screen.

Does it just come down to opinion or is their a time when a screen can really be too big?

I'm mainly asking because I want to go as big as I can. I've seen a decent projector setup with a 98" screen and while I don't remember the room measurements, I don't recall the seating area being too far back. I thought it gave a more realistic theater feel. With bluray and 1080p, I feel the clarity of the picture really deserves a big screen.

In general, how far back should the seating be for 120" screen?


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## Anthony (Oct 5, 2006)

There are a lot of calculators, but the one I use is simple. Sit in your desired location. Put your arms out in front of you, spread your fingers and touch your thumbs together. The distance on the wall pinky to pinky is the ideal screen size. Obviously there is some fudge factor to this measurement 

I learned that from a friend in film school; it is a balance of filling your eyes with light to reduce eye strain and not having to turn your head to see what is going on.


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## Guest (Oct 18, 2011)

That is interesting. I think I can see what your getting at, as far as getting an ideal of a comfortable viewing area. My pinky's are a little freakish and can spread out 180 degrees from my thumbs. Ha.


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## KalaniP (Dec 17, 2008)

I've heard the pinky-spread technique before, too. Personally, I go for a slightly bigger screen than that works out to, usually.

The simple rule of thumb that I've heard is 1.5x screen size to the viewing position (I think I heard that was an old Dolby or THX guideline). That puts the viewing position for a 60" TV at 90" (7.5 feet) away, which strikes me as about right for an immersive viewing experience.


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## Moostache (Feb 19, 2012)

KalaniP said:


> I've heard the pinky-spread technique before, too. Personally, I go for a slightly bigger screen than that works out to, usually.
> 
> The simple rule of thumb that I've heard is 1.5x screen size to the viewing position (I think I heard that was an old Dolby or THX guideline). That puts the viewing position for a 60" TV at 90" (7.5 feet) away, which strikes me as about right for an immersive viewing experience.


Sorry to bump an old thread like this, but I have a question about the quoted reply...

I was under the impression that the optimal viewing-distance / screen-size is determined by the screen WIDTH and NOT the screen DIAGONAL measurement. (although the link below will calculate viewing angles from either width or diagonal measurement!

Is there one that is better than another for this type of calculation?

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

-Maximum SMPTE recommended viewing distance: SMPTE standard EG-18-1994 recommends a minimum viewing angle of 30 degrees for movie theaters.

-Maximum and Recommended THX viewing distances: THX also publishes standards for movie theaters to adhere to for THX certification. THX requires that the back row of seats in a theater have at least a 26 degree viewing angle and recommends a 36 degree viewing angle.

For me:
1. Distance to main viewing location: 11 feet 6 inches
2. Choose Screen Shape: 16:9 (Widescreen TV Shape)
3. Choose Screen Size: (Enter either a diagonal screen size or width):
Choose Diagonal Size = 106 inches
or Width = inches

RESULTS:
35.6 deg. 
Current Viewing angle

40 Feet 
Maximum recommended viewing distance

14.4 Feet 
Maximum recommended SMPTE viewing distance (30 degree viewing angle)

16.7 Feet 
Maximum THX viewing distance (26 degree viewing angle)

11.8 Feet 
Recommended THX viewing distance (36 degree viewing angle)

Screen size to achieve SMPTE minimum viewing angle
*88.5" 16:9 diagonal*

Screen size to achieve THX recommended viewing angle
*107.4 " 16:9 diagonal*

Based on these calculations, my front row seating at 12 feet and rear seating at 16 feet keeps me right in line with the THX recommendations...


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## KalaniP (Dec 17, 2008)

Moostache: Check here for the easiest answer to your question: http://carltonbale.com/home-theater/home-theater-calculator (might give you the same info you already have, but I definitely trust this resource)

"Rules of thumb" are just that. _General_ guidelines designed to get you in the ballpark without too much muss or fuss. They're not intended to be rigid guidelines that apply in every situation.


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## Mark Techer (Jan 17, 2008)

If I may, I'd like to clear something up. That THX 36 degree rule things is actually for CinemaScope[2.39:1], not HDTV [1.78:1] and was designed as a bench mark for actual cinema design. 

SMPTE states that you should not sit closer than 2x the image height and that 3x is preferred and 3.68x the image height [for 2.39:1] is actually the said 36 degrees. 

THX set a preferred and a min spec for their cinemas where the minimum is just 26degrees. This equates to 5.18x the image height. 

So for HT, I recommend using any number from 3.68 to 5.18 and divide your room length by that number. It works for all rooms and is better than guessimating the size the screen.


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## Prof. (Oct 20, 2006)

Mark Techer said:


> SMPTE states that you should not sit closer than 2x the image height and that 3x is preferred and 3.68x the image height [for 2.39:1] is actually the said 36 degrees.


 Mark..aren't you sitting a lot closer to your CIH scope screen than the preferred distance !? I know I am..


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## Mark Techer (Jan 17, 2008)

Prof. said:


> Mark..aren't you sitting a lot closer to your CIH scope screen than the preferred distance !? I know I am..


My front row is 2x the image height away from the screen and is where I like to sit and for Scope, that means the viewing angle is well over 50 degrees.


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## Prof. (Oct 20, 2006)

That's about the same position as where I sit..So we and most other CIH viewers sit way outside the THX or SMPTE preferred angle..and yet both specifications refer to a 2.39 :1 screen!!..
Why should there be a such a huge difference (particularly THX) between preferred and practical!?


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