DXOMARK.com, did you notice

Started Jan 28, 2014 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: DXOMARK.com, did you notice

MAubrey wrote:

If you read their methodology, you'd already know.

They upsize their test images from μ43 sensors to the size of a FF sensor. That essentially cuts all the scores in half, by definition.

But that's exactly what they should do, in my view. Keeping MFT images at one quarter the area of FF images implies that we expect to view MFT images at only half the magnification of FF images (whether in print or on screen). I certainly don't expect that. I expect to view my MFT images at the same display size as those from an FF camera.

Furthermore, MFT lenses don't have much trouble meeting this requirement, i.e., that of performing about twice as well as an FF lens in terms of lp/mm on the sensor so that the image can be enlarged about twice as much and still show about the same resolution.

Instead, I'd say that the primary explanations is that DxO's overall score factors in the capability of the lens to gather light and an f/2.8 FF lens gathers four times more light than an f/2.8 MFT lens (since the area of its image circle is four times larger). In a sense, DxO double-counts this aspect since their sensor scores are based on the same idea. So they penalize MFT two times around, first in their sensor scores and then in their lens scores. However, you can bypass that complication by just ignoring their scoring and look at the measurements, as I do.

Another factor affecting the comparison between MFT lenses and lenses for larger sensors is that MFT sensors currently do not have more than 16 MP whereas APS-C goes to 24 and FF to 36. What DxO measures is image resolution, and this depends not only on lens resolution but also on sensor resolution.

I am not saying that these are the only explanations but they are some of the more important ones.

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