Originally Posted by
BHammy
Agreed: "
...but again, changes/gets better with newer sensors and DIGICs every year!"
The 810A came out 5 months after the 750 and was designed for astrophotography with its specialized IR sensor.
This report shows the 810A being nearly a full stop better than the original 810... a testament to time and additional programming or optimization.
But generally speaking, the larger the pixel size, the better the signal to noise ratio and therefore lower noise
before processing. Compare any 810 images at high ISO to any D4 and the D4 wins. And with larger pixels, is the reason the D4 has 3 more stops of ISO performance over the 810 and the D5 now has
6 more stops of 'capable' ISO over the 810A.
It's the reason why very high end professional sensors use
binning to increase their
s/n
I have been through this debate before. While theoretically pixel size should have better ISO because they have larger collecting area, in practice it doesn't matter that much. One reason for this is that when you have smaller pixel size, you end up with more pixels so the "noise" appear to smooth out a bit.
Also, let's say you have one camera with pixel 4x larger and thus expected to have "smoother" noise than smaller ones. Well when you average over the 4 smaller pixels then it can recover almost all the effect of a one larger pixel. Usually the hardware and software supporting the CCD matters more than the pixel size though, as evident by D750 vs D810/810A.
Again, I'm not saying larger pixels are ........, because theoretically they make a difference. But in practice you never have identical cameras with different pixel size (unless you're comparing 5D vs 5DS), and some smaller pixel size can have much higher dynamic range.
For the record, D7200 and D810 have exactly same pixel size, but performance differ greatly.
What matters a lot with larger pixel though, is that they can retain maximum sharpness at higher f-number. While smaller pixel gets diffraction limited at, say, f/8, larger pixels can go all the way to f/9 before getting diffraction limited. Medium format camera can go all the way to f/11 due to their pixel size. (These are all theoretical limit, btw)