[Edgeyboy]

I am buying an new (plasma) TV and cannot decide whether to buy a 37" or 42" display.

I know there is a rough formula for viewing distance to screen size.

Does anyone know what this is ?

Thanks.

[Zacabeb]

Often 6 times the height of the screen (6H) is considered optimal viewing distance. In the case of a 16:9 set this means the diagonal of the screen should be roughly 1/3 of the viewing distance, and in the case of a 4:3 set it should be roughly 1/4.

I used to have a 41", 4:3 RPTV which I viewed at a distance of 3 meters. I kept being told by people (many of whom are no more astute than to ask me for help all the time) that the screen was way too big. They'd say I should stick to a 25" set, referring to the fist vs. screen method.

The fist vs. screen method is very annoying and inaccurate. It simply involves standing at your intended viewing distance, stretching your arm out and covering the screen with your fist. If the fist covers the whole screen, it is of the right size. If part of the screen shows around your fist, the screen is too big.

Since this results in a very small screen for anyone but Popeye and other people with extremely large fists, I consider it useless. I think it's mostly wishful thinking caused by that most people can not afford very big screens. Or it could be that it's been around for way longer than home cinema and widescreen.

Now I have had a 32", 16:9 set for half a year, and I still often feel the screen is too small for stuff such as movies and video games.

[bh]

I know there is a rough formula for viewing distance to screen size. Does anyone know what this is ?

2.5 times screen height is another formula that I have heard of. However, your best bet is to audition the screens and see what you thing is comfortable (without seeing the fixel structure that you see close up on plasma screens).

[Kevo]

There's no scientific formula, just use your own judgemnet.
I have a 42" and sit at 10ft away. My 'guest chair' is 6ft away, no problems with either.

Go for the 42", it isn't as big as it sounds, you'll soon get used to it. I think you'll find 37" a bit small after a while.

Zacabeb

That's how long I lasted with my 32", then I decided to upgrade to 40". Best thing I ever did. 2.35.1 films no longer look like I'm watching on a stretched portable TV!

[philipb]

I have a 42" plasma, and 2.5m is just about OK. Any closer and pixel structure is visible. 2.5m to 3m is probably optimum.

[Grubert]

There IS a formula. In fact, there are several, but I'll refer to that used for the THX specification:

Viewing Angle
The optimum audience viewing angle for the Cinemascope image (2.39:1) from the screen to the farthest seat in the auditorium is 36 degrees with 26 degress as the aceptable minimum.

In order to meet this criterion, viewing distance must be 1.54 to 2.17 times the screen width. If you sit any further, you won't get a "cinema-like experience" (at least, that's what Lucasfilm says). Assuming a 42"-diagonal plasma has a 93cm-wide screen (allow me to use the SI), you should sit at a distance of 1.43 to 2.02 metres.

Note that I'm not addressing pixel structure visibility or screendoor, which is a whole different problem.

Regards.