Well stated like that your friends claim is actually true. If one of today's sensors was available at the same size with half the pixels, it would undoubtedly have less noise per pixel. But since no such sensors are available it is not that useful a claim...
Yes, sorry if I wasn't clear in my original post. Also, I just re-read my posts in the beginning of the thread and I referred to 5DMKII vs D800, when I intended 5DMKIII vs D800.
In other words, my friend wasn't making historical comparisons (nor he was comparing current sensors to hypothetical versions of the same sensors with lower resolution, but I see what you're saying).
He was comparing current sensors. He was saying that, he would prefer the 6D to the 5D Mark III or, by the same token, the D800, because 6D lower-resolution sensor would produce better images due to less noise.
I was puzzled by this statement having read on-line reviews that seemed to disprove this, at least in such general terms. While this seems to be true at much higher ISO, it's clearly not true at lower ISO, and I am not sure how true it is between 5DIII and 6D (I suspect not true at all). In short, there is much more than just resolution to determine a sensor's noise, so it makes little sense to consider resolution alone.
Here's some fun math.
[...]
If you downsample a D800 to the same resolution as the D700, then you're averaging those three pixels together, giving you somewhere between 1-2 bits of additional useful signal per reduced pixel.
Now, imagine[...]
Lastly, here's your tradeoff. Are you more likely to want 12 megapixels with 16 beautiful bits per pixel, or would you prefer 36 megapixels with 12 beautiful bits per pixel? The former gives you glorious HDR. The latter gives you outrageous high resolution, if your lens supports it, and can be downsampled to give you 14 beautiful bits per pixel at resolutions you actually care about.
My guess is that somebody inside Nikon thought long and hard about these tradeoffs, and had hard numbers for both options, and decided that more pixels was preferable.
Very interesting. While instead Canon decided that 16 beautiful bits per pixel, to stick to your example, would be preferable. Hence, Nikon D800 and Canon 5DIII . Do I understand correctly what you're saying?
Previous Topic
Index
