The maths bit
That all assumes the 2.7m viewing distance - if substantial numbers of people really are viewing HD sets much closer than that, perhaps the BBC will need to rethink the decision to broadcast its HD programming at 1440 x 1080 rather than a full HD.
Glasses won't help if you're too far away...
Not everyone’s watching BBC HD, and for many of us, an HD TV is also something to use with games, or for watching Blu-ray and other high definition content. And the real question, rather than ‘what resolution do we need to broadcast’ is ‘how far away should I sit from my TV?’
If you’re interested in working out the answer to that question, it’s not that difficult. I’ve made some assumptions here, chiefly that you have good or corrected eyesight, and that your TV set has an aspect ratio of 16:9.
In fact, the important measurement is really the height of the picture, or H. For a 16:9 screen with a diagonal picture of size D, you can calculate H using Pythagoras:
The generally accepted figure for human visual acuity is one minute of arc, so we need to calculate the distance at which one pixel is equivalent to that.
The simplest way to approximate this is with a triangle where the vertical side is the height of a pixel, p, and the other sides are of equal length. Bisect that triangle at the centre point, and we have a right angle triangle, with the angle at the eye equivalent to 30 seconds of arc, and the distance to the eye is d. A bit of basic trig gives us our next formula:
Next page: The fear of all sums
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.
