Hi,
I decided to post this as a new topic so it will generate more discussion.
My view is that we should not look at the DxO mark as a figure of merit but the individual measurements. If we do that and compare the Phase One P45+ with the Sony Alpha it is quite obvious that the P45 has an advantage of say 3-4 dB in all areas at minimum sensivity. The sole reason that the Sony Alpha rates higher is that it has higher usable sensivity, and who would doubt that?
One thing that DxO mark seems to indicate clearly that higher ISOs on the P45+ are not for real, no more amplification just underexposure.
The DxO mark quasi ignores that fact that the P45+ plus has about 60% more pixels, so if the A900 is good for A1 enlargements than the P45+ would be good enough for almost A0 and still offering a better image quality than the A900 at the pixel level as long as we are shooting at optimal ISO.
Maybe DxO is a good thing, if we just ignore the single figure of merit and look at the real data.
If we compare the P45+ with Nikon D3x the Nikon is a little better on noise (1 dB at minimum ISO) but the pixel ratio is still the same.
One area where the Nikon shines in DxO test is DR (Density Range). It is less than obvious to me how they have achieved that especially as it seems to be widely assumed that Nikon uses same sensel technology and readout method as the A900. I had a guess that Nikon makes 14-bit readouts by doing a double readout using different on chip preamp settings, but people much more knowledgeable than me have pointed out on this forum that doing that would leave tell-tale signs all over in the "raw" file. A simple truth is that we cannot represent a very large DR in prints. So even if the Nikon files have a real DR advantage if all candidates involved have a DR which is good enough the difference may not be visible in print.
My conclusion is that DxO mark may be entirely relevant when we look at the measurement data at "pixel level". On the other hand I cannot compare pixels between say Phase One P45+ and Nikon D3x, of which I have neither, nor do I have the necessary experience. Michael Reichmann has all the stuff and experience needed, so I have a great trust in his judgments.
One area that I hope that Michael Reichmann will discuss is the difference between different cameras in relatively small prints. Michael Reichmann has himself stated quite clearly that differences between MFDBs and DSLRs are visible in small prints. I obviously don't have the MFDB experience but experiments i have made with the equipment I have sort of indicated that I need to print big to be able to see difference which are very much visible in pixel peeping.
Best regards
Erik
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