The fear of all sums
There are 1080 pixels vertically on a full HD set, so we already know that p = H/1080. Calculating the value for the tangent allows us to put in a real number, and we come up with the following formula for the distance:
A quick calculation suggests that for a 37in display, you need to be 57.74 inches away, or a bit short of five foot. Any further and most people won’t notice the difference.
For comparison, using the ITU recommendation of 3H for viewing distance would come up with a distance of 54.41 inches for the same size screen. And if you want to know the viewing distance in metres, starting with your screen size in inches, then use:
If that seems a bit close for comfort, consider 3D viewers, where the recommendation is to sit only 2H away, according to Panasonic. That, I suspect, is unlikely to happen in many living rooms.
Finally, if you have the reverse question, ‘what size TV do I need to buy for my living room’, it’s easy enough to turn around our last formula. Start with the viewing distance, d in metres, and you can find out the diagonal screen size D you need, in inches, using this formula, again only for a 16:9 set. If you want to buy one of Philips’ super-wide models, do your own sums!
Alarmingly, that suggests that if we really are all watching at the 2.7m distance suggested in the BBC internal survey, we need 68in sets to be able to make the most of full HD.
So, how big is yours, and can you really tell the difference? Tell us in the comments. ®
How to choose the right screen size
COMMENTS
You've got it all wrong....
There are two criteria for choosing a TV size....depending on where you live.
1) It must be bigger than the people who live in the council house next door.
2) It must cost slightly more than what you can afford.
Simples.
Now, being serious (did you realise I wasn't being serious above?), were the tests done with very high bitrate images (I may have missed that in the article)? the main problem I have is the crappy blockiness caused by low bitrate FV channels, although it does seem to have improved since the switchover, but that might be wishful thinking. Unless all the videos were pushed passed the point of blockiness these test would be, like a blunt pencil, pointless.
Obvious stuff
I could have told the researchers that HD on a 32" set was pointless, since to my (reasonably good) eyes this looks no better than normal PAL on a 28" set. Of course, Americans have been putting up with lower-resolution NTSC on mahoosive TVs for years, so there is more of an upgrade imperative there.
HD is only necessary due to the relentless increase in screen size. When you get to 40" and above PAL really doesn't cut it, and 40" is a smallish TV by new standards.
Anyway, we still have a 28" CRT in our living room. The quality of programming is sufficiently bad that we don't feel the need to upgrade. You can't polish a dog's egg.
Wow
You want people who support decimalisation to pack up & leave? TBH I couldn't give a fig what standard of measurement we use here. I just wish we could make our damn minds up and make a bloody decision.
32", so I'm one of those underendowed watchers. But if I'm playing COD, my nose will be right up to it. If, on the other hand, the wife is watching Desperate Housewives my viewing distance becomes exponentially and progressively larger as the tedium unfolds.
@Robert Long 1
Actually, we have two sets of 8 fingers with an extra pair to serve as "carry" and "sign" flags. We should be measuring everything in Hexadecimal--the only number system designed for humans.
-dZ.
Simple but effective. Top Tips (not Viz).
Don't laugh but I do have a solution for people when choosing a screen size. Simply get some large pieces of cardboard with 16:9 ratios of a number of common screen sizes. Then plonk them in the corner of your room or above the mantlepiece, sit back and see if they're the right size for the room.
It may seem silly but it has stopped people I know from buying behemoths that would swallow their living rooms or postage stamps that would give them eye strain.
No, no need to pay me but you could buy me a pint.
