TV Too Big?

[RoddyP]

I have a 51 inch HDTV that we sit about 7 feet in front of . . . is this too close? I have heard that based on the measurements, that's too close. What are the potential harmful effects of having too big of a tv? And if that were the case, wouldn't IMAX theatres be dangerous?

[TheAntMan]

based on measurements...yeah probably a little close. Probably better at 8.5 to 9 feet away. Too close may hurt your eyes. IMAX theaters are big, but you sit at a distance. Can you move back a foot or 2?

[57U]

IMAX has significantly more resolution than HD and far more than SD, which is what a lot of people still watch on their TVs.

Many people recommend a viewing distance of 2 X screen size for most SD programming. For HD (and good DVDs) you can sit closer...

Symtoms - headaches, dizzyness, sore necks from moving your head.

People also don't spend every night at their IMAX.

[bchap]

There is a great website with a viewing distance calculator among many other good reviews and stuff I found last year: http://www.myhometheater.homestead.com/viewingdistancecalculator.html

[57U]

That calculator is fine for HD, but would put you far too close for SD material.

[ruadmaa]

Your TV is not too big, it is a personal choice. If you notice in the theatre some people sit up front while others prefer the back. The same holds true with TVs. Quite frankly, I am from the bigger is better group.

You will have no damage to your vision or anything else. Chances are, looking at a computer screen for extended periods of time is far more damaging than your TV will ever be.

[raidbuck]

I think that the better your TV, and the more you enjoy HDTV, the closer you should be. THe further away you get the less detail you can see and the value of your investiment is reduced.

Many people find that a 42" EDTV plasma is the same as an HDTV one after about 10' distance. I have a 50" DLP and I sit 5-8 feet away, so HDTV is quite glorious. Similarly, SD is awful, so I don't watch it except either upconverted on a digital network feed or ESPN2 (if "my" teams are on). I hope that the Deuce goes away if Comcast ever gets the 2HD channel. YMMV

Rich N.

[cnyreject]

Thought this was an amusing article from a December 23rd, 2004 NY TIMES direct e-mail distribution. It was part of the Technology section and written by David Pogue. Needed to give him credit. But hope he will not mind it.

Check his other stuff out at David Pogue's New York Times Circuits (http://www.nytimes.com/packages/html/technology/circuits.html)

"1. From the Desk of David Pogue: How Close to Sit to the
HDTV? The Physicists Chime In
========================================================

Last week, I asked for your help. I wanted to come up with a
modernized rule for how far away we're supposed to sit from
the TV in the high-definition era -- and I loved, loved,
loved your responses. They ranged from homespun common-sense
nuggets to three-page formulas sent by physicists.

Here's a sampling of the most interesting responses.

* "The easiest way is to use 3.3 times the height of the
screen. Naturally, this is based on true HDTV (720P, 1080I or
1080P) and 20/20 vision."

* "Given the best resolution, you should be sitting
approximately 1.5 times the screen WIDTH away from the
screen. This will give you a viewing angle of about 30
degrees, which will create the immersive effect without
having to move your head too much to catch all the action.
With a lower resolution like EDTV, 2.0 to 2.5 times the
screen WIDTH will probably be more acceptable."

* "Next time you see a film in a theater, take your favorite
seat, then hold up your hand at arm's length, palm to the
screen, and measure the width of the screen in palm widths.
Repeat in front of your home theater and adjust your viewing
distance to recreate the screen size you personally favor."

* "In our house, it was, 'Don't ruin your eyes!' But, of
course, the TV screen was about ten inches across, with a
weird magnifier hanging over it. (Yep, I'm old!)"

* "I don't need no stinking engineers or complicated math to
tell me the optimal distance of screen to viewer. It's like
focusing a camera; move closer or further away until you see
the image that suits you best. I'm sitting closer now that I
have HD."

* "You are, of course, assuming that the viewer has 20/20
vision. As a severely nearsighted TV viewer, my rule of thumb
is usually, 'close enough to annoy anyone else trying to
watch the darned thing.'"

* "Though being closer to the screen is more immersive, there
is a limit to what's comfortable for most people. If the
screen occupies too wide a visual angle, you can no longer
track the action by moving only the eyes, and you have to
start turning the head. This can lead to neck fatigue and can
induce motion sickness in some viewers."

* "David, after you sift through all the feedback here, if
you come up with what seem to be some good rules of thumb,
could you please tell me what size TV to get based on my room
size, rather than what size room to get for my TV? My house
is more valuable than any TV I will ever buy."

* "My only concern about viewing distances is a reminder that
much viewing would be of standard-definition TV broadcasting,
which, because of its lower resolution, needs to be a
consideration, too."

* "In film school (many years ago), I was taught that it has
to do with matching the screen size to the capacity of the
eye's peripheral vision. You want the edge of your peripheral
vision to just catch what's going on at the edge of the
screen. I've tested this over the years and it works for me,
with slight changes as my eyesight has changed."

* "When you look at how far people actually sit from TVs, you
find that for larger sets, it is determined mainly by the
size of the room. Most houses have 10, 12 or 14-foot room
widths and that, minus the width of the TV and the couch
back, is how far most people sit from their TV."

A more detailed response came from Rich Muller, a professor
at the University of California at Berkeley and an old
friend.

* "You don't need HDTV or video experts. You need the council
of a physicist! Fortunately, that's what I am. "Here's the
answer: if the diagonal of the screen is D, and it is HDTV
(1080x1920), then your eye will not see the pixels as long as
you sit at least 1.5 D away. Thus, if you have a 30 inch
diagonal, then you can sit 45 inches away, and even closer if
your eyesight is worse than 20-20.

"Here's the calculation. The resolution of the human eye is
about 1 minute of arc. The sine of that angle is 0.0003.
Pixels closer than this will not be resolved. "If you have a
TV with a diagonal measurement D, and the height and width
are in the ratio of HDTV (1081/1920), then the height of the
screen is very close to D/2. There are 1080 pixels in that
distance, so the average spacing of the pixels is D/(2*1080)
= D/2160. Thus, for a 30-inch screen, the pixel spacing is
30/2160 = 0.014. The number of pixels per inch is about 70.
There are more pixels per inch for small screens, and fewer
for large screens. If you are observing the screen from a
distance R, then your eye resolution (with angle A = 1 minute
of arc) will be R x sine(A) = 0.0003 R. This distance must be
bigger than the pixel size, so we set 0.0003 R = D/2160. That
gives R = D/(2160 x .0003) = 1.5.

"That's the rule of thumb that I came up with. At this
distance, the horizontal dimension of the screen will cover
82 degrees of your field of view! (Your entire field of view
is about 180 degrees.) So -- sit up close and be swept away
by the clear visual experience."

My favorite response, though, came from this clever reader:
"Here is the answer to how far to sit from your HDTV," he
wrote. "'The way I see it, the closer you can sit without
seeing the screen-door effect, the more the picture will fill
your vision, and the more immersive the movie will be.'"

Of course, that second sentence came straight from my
original column. It seems that in posing the question, I
unwittingly provided my own answer!

Thanks again to all who participated -- this was a really
great way to get to the bottom of a difficult debate. Next
week's assignment: Is there life after death?"

Just kidding.

David Pogue

[gparris]

Usually I tell folks that ask me or those I do setups for that the best viewing distance is twice the diagonal of the HDTV set as a compromise because unless you have a remote control for your set's position in the viewing room or the seats can move in alignment with the channel viewed or source selected, it is impossible to have a perfect distance at all times. :whistle:

If 1.5 or 2 times the diagonal for 16:9 sets is recommended for HD sources, ones that are not stretched or upconverted, great...but there will be times when the source is analogue, DVD or God-forbid, VHS tape (yes it occurs) and then you have more of a 2-3 times the diagonal situation.
I tell them that depending on their viewing habits-what they use the HDTV set for, is what will determine their useful distance.
The digital channel watcher with some HD and the DVD viewing more or less casual gets to plot a 2.5 times distance, for example. :D