D5 wrongly reviewed by DXOmark

Started Jul 1, 2016 | Discussions thread
rhlpetrus Forum Pro • Posts: 26,131
DR vs SNR and high ISO
1

whumber wrote:

eno2 wrote:

Hi everyone,

I don't know what happened to DXO lately but I'm starting to see wrong evaluation of cameras. In this thread I will show the example of Nikon D5.

If you compare it on DXO to the new Canon 1Dx mk 2 (a fantastic camera nonetheless), you'll get the impression that the Canon is superior both in DR at lower ISO's (I have no doubt about that) and also regarding noise. Then, if you try comparing samples from both cameras at different ISO values(from any review sites), the truth is quite different, the Nikon is a little bit better than Canon until ISO 52.000 and a lot better beyond (probably with one ISO stop). The funny thing is DXO states that at ISO 200K, the D5 is one full stop worst than 1Dxmk2 and the reality shows exact the opposite.

2 ISO stops deviation from their measurement is quite severe I'd say and their reputation must answer to those false value.

Below I attached two examples taken from Dpreview and compared them with DXO measurements.

What are your thoughts about this?

Dynamic range really does a better job predicting high ISO performance than SNR since we tend to notice the noise more in shadow regions. If you look at the DR plot for the D5 vs 1DXII then I t hink you'll find that the DxO measurements make more sense. The single number scores, especially the ISO/sports score, are basically worthless.

I have mentioned this before, but I'm still waiting for the technorati here to explain why DR is a better predictor than SNR for high ISO visual noise perception. The issue is that DxO, despite using both curves for establishing the high ISO score, in principle, ends up using the SNR 18% curve, which reaches the cutpoint earlier, and that's what determines their high ISO score.

Maybe, if one uses all SNR curves carefully, considering lower saturation curves as well, one might get a better predictor of high ISO performance.

Anyway, for the first time in DxO, the high ISO cutpoints for D500 and D5 are lower than one would expect from their visual results (and from their DR curves).

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Renato.
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