Daaaaaaaamn! Check out the D5200 sensor!

Started Jan 24, 2013 | Discussions thread
Steen Bay Veteran Member • Posts: 6,978
Re: Daaaaaaaamn! Check out the D5200 sensor!

dethis2 wrote:

Jack Hogan wrote:

Steen Bay wrote: btw, it's not quite clear whether the D5200's QE is 53% or 65%. If it's 65% like sensorgen's frontpage says, then that would be a new record.

Imho its QE is quite a bit lower than that, well below 50% using Sensorgen units. The other Sensorgen figures check out, so since DR, read noise, FWC and overall SNR are excellent, all this probably means is that the CFA is a bit stronger than usual, and that can only lead to better color - which you can actually see in the improved Color Sensitivity performance measured by DxO (vs the D7k, for instance). So once resolved the banding issue, this is indeed an excellent, state-of-the-art, little sensor.

D5200 has a tiny bit higher SNR18% from D7000 so it should have a tiny bit higher QE.

D5200 has a much lower FWC than D7000 and a bit lower than D3200

D5200 -> 27517

D3200 -> 28729

D7000 -> 49058 which normalized to 24Mp is 16/24*19058 = 32705

If we see DxO analytical SNR curves for D5200, ISO100 curve is very near ISO 200 at all it's lenth which to me is evidense that ISO 100 is in reality a bit higher, say ISO125.

Yes, the SNR at ISO 100 seems lower than it should be, but according to DxO the measured ISO at camera ISO 100/200 is ISO 69/138, so the sensor's saturation capacity at ISO 100 should be 2x higher than at ISO 200. Not quite sure what's going on here.

There are some raw files at http://www.ephotozine.com/article/nikon-d5200-review-21020#Performance.

I inspected the raw histograms with rawdigger. At all ISOs >=200 the green histograms (which are not affected from WB preconditioning) have gaps every 5-6 levels. The only solid histogram is the one for ISO100. Counting the gaps I find a repeatable pattern of 4 gaps every 23 raw levels so we have a division 23/19 = 1.21

It looks like ISO100 is ISO121 compressed ..

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cpw
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