D3 sensor efficiency

Started Nov 18, 2007 | Discussions thread
DuncanM1 Contributing Member • Posts: 817
Re: D3 sensor efficiency

I have calculated preliminary gain values for the Nikon D40X:

Full well = 55700e
ISO100 IG =
IS0800 IG = 1.63
ISO 100 read noise =
ISO800 read noise = 9e

I have to recheck my figures and do some plots for ISO200, 400 and
1600, but this seems like a very efficient sensor.

The ISO400 Gain values are probably on the order of 3.3 which actually exceeds the D300 or 40D but these values verify the DR data from the 40D Images Resources Imatest results:

Model 1.0(Low) 0.5(Medium) 0.25(Med-High) 0.1(High)
Fujifilm S3 Pro
(Adobe Camera Raw 2) 12.1 11.7 10.7 9.0
Nikon D40x
(Adobe Camera Raw 4.1) 12.0 10.9 10.3 8.9
Nikon D40
(Adobe Camera Raw 4.1) 11.9 10.9 9.89 8.3
Pentax K-100D
(Adobe Camera Raw 3.6) 11.3 10.3 9.51 8.23
Pentax K10D
(Adobe Camera Raw 3.7) 10.6 10.0 9.29 8.19
Canon EOS-1Ds Mark II
(Adobe Camera Raw 3) 11.2 10.3 9.4 8.14
Nikon D40x 10.8 10.0 9.42 8.04
Fujifilm S3 Pro -- 9.9 9.4 7.94
Canon Digital Rebel XTi
(Adobe Camera Raw 3.6) 10.8 9.88 9.18 7.84
Canon EOS-5D
(Adobe Camera Raw 3) 11.0 10.4 9.21 7.83
Canon EOS-40D
(Adobe Camera Raw 4.2) 11.2 10.1 9.26 7.72
Canon EOS-5D
(Camera JPEG) 10.2 9.68 8.82 7.65
Nikon D200
(Adobe Camera Raw 3) 10.6 9.65 8.96 7.61
Nikon D80
(Adobe Camera Raw 3.6) 11.1 10.4 9.42 7.51

( http://www.imaging-resource.com/PRODS/E40D/E40DIMATEST.HTM )

I can confirm that the D40X does, indeed, have 12 stops of DR, in the Low (engineering) category as measured by IR. This makes the D40X sensor one of the most efficient sensors on the market, and at low ISOs it will exceed the performance of the D300 and 40D.


ejmartin wrote:

As a companion to the dynamic range measurement reported here:
I have now also measured the (full well) capacity of the pixels of
the Nikon D3. I found that at the base ISO of 200, the full well
capacity is 53,400 electrons, a new high among DSLR's. The previous
record holder was the Canon 1Dmk3, whose well capacity at ISO 200 is
about 39,500.

To put this in perspective, if we scale up the 7.2 micron photosites
of the 1Dmk3 to the size 8.46 microns of the D3 photosites, the
scaled up photosites would have 54,600 electrons full well -- the
same within experimental error. It seems then that the D3 and the 1D
mark 3 have about the same level of sensor technology, just different
choices for sensor size and pixel pitch. The read noises are
comparable too: I found 4.9 14-bit raw levels of read noise at ISO
200, 14.3 at ISO 1600, and 23.3 at ISO 3200 for the D3; and for the
1Dmk3, 4.9 @ISO200, 12.1@ISO1600, and 23.8@ISO3200.

So it looks as though the D3 will indeed be the high ISO champion, by
about .2 stop per pixel in midtones and highlights (and marginally
even better as a percentage of image area due to having 20% more
pixels, pushing the noise to finer spatial scales where it is less
noticeable); the above figures tell us the relative photon noise
levels when viewed at 100% (at the pixel level) are essentially the
same as the ratio of pixel pitches. In shadows, the read noise
dominates and the performances of the two cameras are roughly the

Note that my analysis was carried out on the raw files themselves,
prior to raw conversion that adds additional uncontrolled effects to
the image. The pixel capacity is a property of the sensor itself. A
lot of high ISO samples from the D3 are jpegs exhibiting strong noise
reduction (especially chroma noise); the direct analysis of the raw
files renders that issue moot.


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