Precise viewing distance
 

I'm planning a home theater with an HDTV. I once knew more about
visual acuity than I remember now, but I remember there's a
theoretical optimal viewing distance that's a function of screen size
and resolution. I want to go for an HDTV standard resolution signal
(something like 1920 by 1040) same as (I think) 1040 P. Can anybody
tell me how to calculate viewing distance in feet as a function of
screen size and resolution? The people at the store know what I'm
talking about, but so far, nobody has been able to help me size a set
to my room.

Precise viewing distance
 

"dubina" wrote in message
ups.com...
I'm planning a home theater with an HDTV. I once knew more about
visual acuity than I remember now, but I remember there's a
theoretical optimal viewing distance that's a function of screen size
and resolution. I want to go for an HDTV standard resolution signal
(something like 1920 by 1040) same as (I think) 1040 P. Can anybody
tell me how to calculate viewing distance in feet as a function of
screen size and resolution? The people at the store know what I'm
talking about, but so far, nobody has been able to help me size a set
to my room.


I had the same question about a month ago, before I bought a Sony Bravia
KDL-46xbr2 LCD TV. Here is a great link that should help you make that
decision:

http://ezinearticles.com/?TV-Viewing...eater&id=37449

It certainly helped in my case. Incidentally, I sit about 80 inches away
from the screen (which is 40 inches wide). IMHO I think it would be ok to
sit even closer to a High-Def station, but Standard Def signals would not
really be desirable.

Hope this helps,

Robert A. Cunningham

Precise viewing distance
 

In article . com,
dubina wrote:
I'm planning a home theater with an HDTV. I once knew more about
visual acuity than I remember now, but I remember there's a
theoretical optimal viewing distance that's a function of screen size
and resolution. I want to go for an HDTV standard resolution signal
(something like 1920 by 1040) same as (I think) 1040 P. Can anybody
tell me how to calculate viewing distance in feet as a function of
screen size and resolution? The people at the store know what I'm
talking about, but so far, nobody has been able to help me size a set
to my room.

First, it's 1080.

You may be thinking of this chart:
http://hdguru.com/wp-content/uploads...ance_chart.pdf
There's an article associated with it, but I don't have the link.

Anyway, I'd take care with any such chart which is easy to
construct, but contains so many assumptions that it is only somewhat
relevant (and very much abused). It's based on, as you say, visual
acuity, and pixel angular size (combo of pixel size and viewing
distance). But consider (using a 50" as an example):

The listed "optimal viewing distance" for a 1080p is 78.43". Well,
what happens at say 60"? It means you would benefit from higher
res, but there's nothing to say you won't enjoy it more than at the
78.43". What happens at 100"? In theory, a bit of the 1080p is
"wasted", but it is still better than a 720P. ... if ...

You have the theoretical 20:20 vision it assumes. (since people can
vary by 10%, 20%, 200% or more, that is more important than this
table).

What about the fact that most of the material you watch will be in a
different native resolution? Sure, your TV will rescale, but it
won't be able to create better rez than in the original media.
Watching analog SD on a huge TV that is optimal for your viewing
distance and 1080p may produce very unsatisfactory results.

Anyway, use it as a guide. But don't treat it as gospel. I use a
50" 720p set and watch from about 10-11 ft (okay, about what the
chart recommends). I originally had it closer, but moved it back as
poor quality and/or low res signals looked poor.

Precise viewing distance
 

On Thu, 14 Jun 2007 05:56:28 GMT, JimK2 wrote:

On Wed, 13 Jun 2007 15:05:21 -0700, dubina wrote:

I'm planning a home theater with an HDTV. ...
Can anybody
tell me how to calculate viewing distance in feet as a function of
screen size and resolution?

Dish recomends viewing distance (feet) times 7 for screen size
(inches)- 60" display 8.57 feet viewing distance

Viewing Distances Based on Visual Acuity (60" display 7.8 feet viewing
distance)
http://www.myhometheater.homestead.c...alculator.html
http://www.burnyourbonus.info/hdtv-faq/faq3.html

For 720p display you probably want 20%-30% smaller screen. Im 9.5 feet
from 60 inch display.

The problem with that calculator and most charts based on the normal
human resolution is that they assume that you should dimension your
display so that you can see the individual pixels. This, in an attempt
not to "waiste resolution".

The link that Robert posted is better in that way and it tells you
right away not to sit so close so that you can see the pixel
structure. The basis for all sampled systems is that you should not be
able to resolve the samples.

This was the link:
http://ezinearticles.com/?TV-Viewing...eater&id=37449

The actual numbers where the pixel structure gets noticable will be
different with different display type. The most critical in this
respect is the direct view LCD or PDP panels because the pixels are
sharp.

Based on my own testing (with LCD panels in sizes around 32-40" but it
should be scalable) is that I want a distance of more than
approximately pixel_size * 4000. This is to be sure that I dont see
the pixel (and subpixel) structure but instead perceive a smooth
natural looking image.

Using a projection system I believe that the distance/pixel_size ratio
can be reduced somewhat but I haven't determined a number.
/Jan

Precise viewing distance
 

On 2007-06-13, dubina wrote:
I'm planning a home theater with an HDTV. I once knew more about
visual acuity than I remember now, but I remember there's a
theoretical optimal viewing distance that's a function of screen size
and resolution. I want to go for an HDTV standard resolution signal
(something like 1920 by 1040) same as (I think) 1040 P. Can anybody
tell me how to calculate viewing distance in feet as a function of
screen size and resolution? The people at the store know what I'm
talking about, but so far, nobody has been able to help me size a set
to my room.

Here's another article with charts:

http://www.carltonbale.com/blog/2006...p-does-matter/

-Bill
--
Sattre Press The King in Yellow
http://sattre-press.com/ by Robert W. Chambers
http://sattre-press.com/kiy.html

Precise viewing distance
 

"Jan B" wrote in message
...
On Thu, 14 Jun 2007 05:56:28 GMT, JimK2 wrote:

On Wed, 13 Jun 2007 15:05:21 -0700, dubina wrote:

I'm planning a home theater with an HDTV. ...
Can anybody
tell me how to calculate viewing distance in feet as a function of
screen size and resolution?

Dish recomends viewing distance (feet) times 7 for screen size
(inches)- 60" display 8.57 feet viewing distance

Viewing Distances Based on Visual Acuity (60" display 7.8 feet viewing
distance)
http://www.myhometheater.homestead.c...alculator.html
http://www.burnyourbonus.info/hdtv-faq/faq3.html

For 720p display you probably want 20%-30% smaller screen. Im 9.5 feet
from 60 inch display.

The problem with that calculator and most charts based on the normal
human resolution is that they assume that you should dimension your
display so that you can see the individual pixels. This, in an attempt
not to "waiste resolution".

The link that Robert posted is better in that way and it tells you
right away not to sit so close so that you can see the pixel
structure. The basis for all sampled systems is that you should not be
able to resolve the samples.

This was the link:
http://ezinearticles.com/?TV-Viewing...eater&id=37449

The actual numbers where the pixel structure gets noticable will be
different with different display type. The most critical in this
respect is the direct view LCD or PDP panels because the pixels are
sharp.

Based on my own testing (with LCD panels in sizes around 32-40" but it
should be scalable) is that I want a distance of more than
approximately pixel_size * 4000. This is to be sure that I dont see
the pixel (and subpixel) structure but instead perceive a smooth
natural looking image.

Using a projection system I believe that the distance/pixel_size ratio
can be reduced somewhat but I haven't determined a number.
/Jan

Jan B.,

That was a good link! I wish I had discovered it before I bought my TV.
My calculations on viewing distance and screen size turned out to be right,
but I had to do a lot of reading before I came to that conclusion. Your
link would have saved a lot of time for me. Thanks, I appreciated it.

Robert A. Cunningham