The Economist article on mirrorless cameras

Started 6 months ago | Discussions thread
Jerry Fusselman
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In reply to Erik Magnuson, 6 months ago

Erik Magnuson wrote:

Jerry Fusselman wrote:

Where did you see DXOmark test results? I didn't see any.

Here you go:

http://www.dxomark.com/Cameras/Compare/Side-by-side/Sony-A7R-versus-Canon-EOS-6D-versus-Canon-EOS-5D-Mark-III___917_836_795

Did you actually look at the graphs or the single headline number?

Here is the SNR 18% graph (where it crosses the 32dB line is the low light score).

Here is the DR graph:

I welcome the extra issues you are bringing up here.  I'll respond carefully (for once).

  1. There is no such thing as "all of the data," because you can always get more.  There are many sources of data on this issue, and what to emphasize becomes a personal choice.  I've been running my own tests.  By the way, (even) the Sony Alpha a6000 easily beats my Canon 5D M3 in tripod testing at base ISO for landscapes.  In particular, the extra dynamic range from the a6000 at ISO 100 is wonderful.
  2. One of my personal choices is hard to justify in brief, but I believe it does not pay to take either of these two cameras beyond ISO 1600.  I now always use post processing to lighten the image when needed when my manual exposure settings combined with ISO 1600 give inadequate weight.  This is a long subject, and I don't want to justify it here.
  3. To me, therefore, the key sensor settings that matter are primarily ISO 100 and 1600.
  4. Yes, I looked at the five curves under the Measurements tab, and all five matter, but I didn't want to get bogged down in so much detail.  Any subset of that detail can look like cherry picking.
  5. DxOmark needs to go back to graphing school, for the dots at each ISO are way too far too the left relative to the x-axis.  That is, the first dots above are for ISO 100 (I'm almost sure), even though they look like they are for ISO 75 or so.
  6. So let's look at 1600 in these graphs, shall we?  That's the most relevant to me for low light with these two cameras, as I explained above.   In all cases (other than a tiny difference in ISO sensitivity---the least important of the five in this comparison), the A7r is either slightly better or much better (color sensitivity, which you omitted).

Since the A7r's sensor is better in every way that matters to me in low light, I would say it is false to call it worse, and that's what I have been trying to show in this part of the thread.

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Jerry Fusselman

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