Analysis of DxO 5DM3 low-light ISO score (vs D800)

Started Apr 19, 2012 | Discussions thread
dosdan Contributing Member • Posts: 505
Re: Analysis of DxO 5DM3 low-light ISO score (vs D800)

Horshack wrote:

Where the difference comes in is the color depth. At nominal ISO 3200 the D800 has a depth of 18.9 bits and the 5DM3 at 17.8 bits (5DM3's 17.8 bits is below DxO's 18-bit threshold for the low-light ISO score). Even after backing in the 19.1% measured ISO difference the D800 still leads here. It's not clear how much weighting DxO gives the color depth but based on their description they give extra "points" for performance that measures above their threshold minimums, which for color depth is 18-bits.

This topic was also covered in ths DXO forums post:,747.msg1312.html#msg1312

The important part is the reason for the difference in the CS score of Canon vs Nikon.

As to the DxOMark Score weighting, that's covered here:,724.msg1234.html#msg1234

I've updated the linked spreadsheet in that post. The calculated 5DIII score of 80.7 agrees well with the published score of 81.


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