Was discussing today and realised I don't know the answer, and it might be out there on the Internet but I sure couldn't find a definitive answer.

Sooo...40 and 50 inch 1080p TV. They both have exactly the same number of pixels, but one is around 10 inches larger. What is going on with those 10 inches and how come they both have the same number? Are the pixels just larger?

Your answer is already in your question.

ETA: I mean, I know what you are getting at. You are wondering if there was maybe a standard size pixel that just got surrounded by space the larger the screen. But that wouldn't work, as it would affect the picture.

Yes in that case, it is that simple, the pixels are larger and so is the pixel pitch on the larger "diagonal size panel".

That's sooo confusing. So the pixels are larger on a larger telly, which means you get a less clear image at the same distances?

It's all very confusing... I do understand is, but with a bigger TV you have to sit further away - LOL. Stupid technology!

Thanks for the replies! Still confounded.

But that's essentially why they've developed higher resolution sets (4k = 3840x2160 pixels), because of the trend towards larger screens.

So if you sit close enough to see the dots, you need a TV the same size with more pixels, or sit further away. Personally, my plasma TV dots don't bother me at all if I sit close enough to see them.

The "clarity" is the same. Same number of pixels. At the same viewing distance the larger one has a larger area, so will appear slightly more pixelated.

You would have to be close enough to discern pixels in that case, that's too close.

Sat further away you just have a larger area with exactly the same.

If you sat further from the 50" such that it was the same visual size as the 40" then there would be no difference.

As has already been said, the answer is already in your question - obviously it has larger pixels, because it has the exact same number in a larger screen.

The point of a larger screen is so you can view it from further away, although to be fair at 1080 you can't see the pixels at any remotely sensible viewing distance.

You can just about see HD pixels at 3 times picture height
And Uhd 1 pixels at 1.5 H .....
But most in the uk view at over 5 H
See Katy Nolands bbc white paper http://downloads.bbc.co.uk/rd/pubs/w...les/WHP287.pdf

I think this is similar to the bitness of mobile phone camera sensors. The size of the sensor is as important, or more important than the number of pixels

Because most people view their TV from quite a distance away there really won't be much difference between 40" and 50"

Basically if you can't see the pixels then you can't see the detail - it is the pixels that give you the extra detail in the first place ... that is why there is little point having a 4K TV below 50".

Not stupid technology, basic simple physics.

Kell Factor, anyone ?

Interesting that it applies to all analogue, digital and even mechanical sampled systems. Kell discovered it while working on mechanical TV systems I think in the 30's

If you really want to open a can of worms ask the Hi Fi world about its relevance to the frequency response of CDs.

Must say I've never heard of the 'Kell Factor', and presumably HiFi people wouldn't have either?, but WOULD have heard of the 'Nyquist Frequency'

Kell noted that if you point a camera with a vertical resolution of say 100 lines at a chart with 100 alternate black and white lines the chart will be resolved but if you pan down by half a line you just get a grey field as the camera is seeing half a white and half a black line on each of its scanned lines. For real pictures the vertical resolution is therefore lower and the same applies to the horizontal resolution on digital systems that are of course sampled. The Kell effect can be clearly seen on the vertical resolution part of the standard SMPTE test pattern used for telecine alignment and I used to use it to explain it to junior staff, the horizontal section was good for explaining PAL cross colour years ago.

All textbooks happily show the Nyquist limit at the point where the two half cycles of a sine wave can be measures with two samples. However if you move the sine wave by a quarter of a cycle the o/p is zero simply due to dear old Kell's factor.

Whether it matters or not is a matter of opinion, we don't look at test charts and frequencies above say 15kHz on CDs are likely to be the tizz of cymbals and so on, but if you want to upset some know all Hi Fi nut it's a great conversation stopper. I do wonder if the improved benefits that some people can hear on wide bandwidth sources are due to the wider frequency response or the higher sampling frequency moving any Kell effects out of the range of human hearing. Personally I'm too old for such improvements to be audible to me.



https://en.wikipedia.org/wiki/Kell_factor