: Viewing Distance


waketech
2008-12-06, 10:41 PM
Just wondering what the rule of thumb is for the size of tv and distance needed to sit from that tv for optimal viewing ?

Thanks

timbo
2008-12-06, 11:51 PM
http://www.digitalhome.ca/forum/showthread.php?t=76075...for a rule of thumb.

There is a weath of information available from the Digital Home FAQs thread.
Access all the FAQs quickly from the blue toolbar at the top of page. Click on Help to find the quick link.

lharvey
2009-02-14, 07:00 AM
I'd love to know how people come up this these viewing distances. They never explain and, of course, they never explain what criterion is being used to define "optimal." My calculations are very differ. I would base distance on 2 criteria, visual resolution and size of the focal vision area.

An HDTV is 1920 pixels wide. Maximum visual resolution is 60 cycles/degree. 1920/60 gives 32 cycles. So you want the screen to be slightly less than 32 degrees wide. A 50" diagonal TV is 43.5 inches wide. If you sit at 72 inches, the the screen size is arctan(43.5/72)*180/pi= 31 degrees. This is just about right. Further, focal vision, the part you use for inspecting the world is the central 30 degrees, so the screen is also optimal size by this criterion too.

6 feet is the optimal distance.

There are two caveats. People with long resting accommodation and vergance distances may have eye strain problems. Also, you might seen vernier offsets which require much higher acuity, in some images like cartoons.

57
2009-02-14, 09:58 AM
There is a visual acuity link in the FAQ already posted - point 8. This S&V article corroborates your 6' number for a true 1080i/p picture, however, most people feel that this is too close to watch for a long time and also, many people may watch SD DVDs, or SD programming, or poor quality "HD", therefore 6' would again be too close for them. Hence the rule of thumb...

If you took the time to read the FAQ, there is no "best distance" for anyone and it would depend on what you're viewing and your preferred viewing habits - again a rule of thumb is just that - not something that one person in particular may be happy with.

See point 7 of the FAQ, which has a link to a poll showing people viewing anywhere from 1.2X screen size to more than 3X screen size.

lharvey
2009-02-16, 07:32 AM
You are wrong. There is an optimal viewing distance for the criteria that I used and I just explained how to calculate it. There is may be preferences, but preferences are not the same as optimal conditions.

If you took the time to read a basic vision book, you might understand something about this.

57
2009-02-16, 04:35 PM
Your post assumed a certain resolution of 1920 pixels across the screen. It's a fallacy to believe that you can watch SD programming at the same distance as HD programming, just because the TV has a certain number of pixels, This is because SD material doesn't have the necessary clarity, even after upconversion. Hence my clarification.

Also, not everyone has identical visual acuity or field of view.

Books are great for theory, but real life isn't quite so neat and tidy.

nickleinonen
2009-02-16, 08:11 PM
Books are great for theory, but real life isn't quite so neat and tidy.

well said..

Ocean Tuner
2009-02-18, 10:02 AM
Didn't see any reference to it in this thread, Check out this link guys:

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

Cheers
OT