On 1/25/2014 6:00 AM, Bob Whitmire wrote:
> No dog in this fight,
!
> but found this on Adorama and thought it interesting. Rates the best High ISO
> cameras.
>
> http://tinyurl.com/l3vpxl7
It seems I just don't 'get' DXOMark. They make judgements and pick winners over
differences that not only will never be
visible to anyone, but are likely less than normal sample variation.
They rate low light ISO on some mechanically derived noise factor, but they
have nothing to say about what the noise
looks like.
And they can't, of course tell one how the noise responds to NR. So, in the
end, they provide little or no useful
information for the user who want's to know what will come out the other end of
the whole process of taking and post
processing. What will the image LOOK like?
The Raw sample images of standard test subjects on dpreview provide far more
useful information for the actual
photographer. (Have the other sites with standardized subjects added Raw?)
I just looked at their comparison of E-M5, E-PM2 and GX7. The PM2 has the same
sensor and processor as the M5, but gets
a higher low ISO score. If one knows how ISOs work, there is no real
difference, but as a raw numbers, it looks significant.
The GX7 scores worse than either of the Olys. I have all three, I've processed
a lot of low light images. The GX7 has
slightly lower noise, not higher, at least up to ISO 6400. To me more
importantly, the GX7 noise responds better to NR,
AND, when noise is reduced the GX7 has FAR fewer 'wormy' artifacts
left/revealed than the Olys at the same ISO. At the
end of the day, the GX7 is, as a practical, visible matter 1 to 2 stops better
than the Olys in high ISO noise. This is
a much greater difference, and in the opposite direction, than DXOMark gets.
DXOMark says the Olys actually under perform rated ISO, which would make the
differences even greater. I've done no
serious comparisons, but when I was taking ISO test shots of a real life
subject, the exposures were the same and the
resulting images looked the same in exposure visually and on the histogram.
(Color, contrast, saturation, etc. are
different, via ACR.)
If their measurements and ratings are clearly inaccurate for cameras I have,
How can I put any credence in their ratings
of other cameras? I accept that much larger, heavier, more expensive, FF
cameras have better low ISO performance than my
µ4/3 gear. But from the DXOMark data I have no idea how big the difference may
be.
I understand our culture's obsession with measurement, rankings and winners.
But when the rankings do not reflect actual
performance differences, I can't see how they are of use. What the H are they
measuring? Why?
Lab Testy Moose
--
What if the Hokey Pokey *IS* what it's all about?
--
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