Sun 12-Feb-12 06:54 PM | edited Sun 12-Feb-12 06:57 PM by bclaff
I'm returning to this thread to reply to a queries posed elsewhere rather than take that thread off topic.
That query (in magenta) was: I have looked at the D800 data on your website. I am curious as to how you measured the Noise from the NEF.
Read noise was measured using the optical black data in an area of the NEF that is not used to make the image. For some technical background you could look at Read Noise – Optical Black at my site.
As you know, the size of the D700 Sensor pixel is almost 2x the size of the D800 Sensor Pixel . S/N suggest to me that with the larger D700 Sensor (8.45 micron) vs the 4.8 micron D800 Sensor, you get twice as much light for the D700 compared with the D800 Sensor.
The Question is how does the Noise for these two different sensors compare? I know you have done some Read Noise calculations for the D800 at different ISO's . It would be very useful once the D800 is at hand to do a like to like comparison of Read Noise for the D800/D700. Then one can get some good idea on a comparison of the S/N for the D700/D800.
However the S/N is also dependent on the Shot Noise, the Dark Noise as well as the Read Noise. These are very difficult to measure independently .I think to get a real quantitative comparison , one would have to calculate like images from a D700/D800 using the same lenses, the same settings everything and compare the raw NEF files from both cameras. Gut feel tells me that unless Nikon has put in some extraordinary noise reduction technology in the D800, if like for like, a raw NEF D800 at higher ISOs will display lower S/N to a similar NEF from a D700 for the same settings, that is the D700 will have a better S/N at higher ISOs. What is interesting , Nikon does not seem to publish Noise Sensor Data or S/N comparison for their different sensors. If they do, let me know where I can find it.
Some have suggested under sampling a D800 raw NEF to 12 MB, but all that does is just apply an averaging or a smoothing function over the image.
You are basically asking to compare the D800 to other cameras on a Signal to Noise Ratio (SNR) basis without regard for the size of the photosite.
The best comparison for that purpose is the Photographic Dynamic Range (PDR). You can see a PDR Chart at my site that includes estimates for the D4 and preliminary data for the D800.
Note that technically, PDR is largely a function of read noise and gain; and that gain is interchangeable with Full Well Capacity (FWC).
Additional questions are welcome but please look at my site to see if you answer is already there!