Yikes! The rumored Nikon D800.

Started Oct 5, 2011 | Discussions thread
bobn2 Forum Pro • Posts: 60,661
Re: Yikes! The rumored Nikon D800.

orpheo wrote:

Hm, interesting.

Now I wonder:

  • Why would Nikon not put more of these more efficient pixels on the D3s' sensor two years ago - or lately the D7000's sensor - if pixel size doesn't matter, resolution is so utterly important and/or sells so well?

There are at least two reasons. First, the source of the pixels is different, d3s is Nikon, D7000 is Sony. Second, the pixel count of the D3s was limited by the EXPEED processor - they could have doubled the pixel count, but then it would have been a 4.5FPS camera, and wouldn't have competed in its intended marketplace.

As it was, putting this excellently efficient sensor in the existing D3 allowed Nikon to build a 'mid life kicker' which stole much of the 1DIV's thunder.

  • And only two years after the D3s it's supposedly possible to triple the pixel-count without losses?

The pixel size of the D3s was way above what was needed for that technology, it was dictated by the speed consideration, above. The Nikon 1 series has pixels with 1/4 of the area and much the same performance.

I know, you didn't actually say that, but the way you argue, that seems to be the conclusion to me.

One possible conclusion, not necessarily the right one.

Propably you do have access to more information and/or know better how to interpret it, but all I can see so far is, that comparing raw-files of roughly the same generation of equally sized sensors, better low-light performance always goes along with bigger pixels.

Give an example - I doubt you'll actually find one,

Based on that, my conclusion is, a 36MP-FF-Sensor the likes of the one used in the D7000 wouldn't even come close to the low-light-performance of a D3s. So how much progress is possible in one year with basicly the same sensor type? My optimistic guess would be: 24MP max to keep the level of the D700.

Simply, your conclusion is wrong and based on a false observation. Your guess is pessimistic. We can accurately predict the performance of the three sensors from the measurements DxO has made of the pixels.
D700 pixel has 38% quantum efficiency and 5.3 e- read noise
D3s pixel has 57% quantum efficiency and 2.8 e- read noise
D7000 pixel has 48% quantum efficiency and 2.5 e- read noise (4.3 e- at 12MP FX)
So for the same exposure, the photoelectrons collected compared to D3s, will be

D7000 FX 0.84x, giving a highlight/mid-tone noise of 1.1x, basically 0.25 stop worse.

D700 0.66x, giving a highlight/mid tone noise of 1.25x, basically 0.6 stop worse
In the shadows, again based on the D3s we'd get

D7000 FX, noise is 1.54x, D700 noise is 1.9x. One way of looking at the combined effects is 'tonal range', as defined by DxO. In this case we get, at 25k ISO
D3s - 5.5 bits
D7000 FX - 5.1 bits
D700 - 5.09 bits
Thus this will be a little better than the D700, a bit behind the D3s.
This is based on measurements and analysis.

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