On 5/17/2014 7:25 AM, DZDub wrote:
On Sat, May 17, 2014 at 4:14 AM, Moose de Worm <olymoose@xxxxxxxxx> wrote:
All digital cameras I've used have little pixel level artifacts I call
worms. Hardly ever noticeable in contemporary bodies at base ISO, they
increase in number/size/intensity as the ISO goes up. It's easy to miss
them in noisy files, then they show up after NR. It's also easy to think
they are artifacts of the NR. However, when flipping the NR layer off and
on, it becomes apparent that they were there all along, simply masked by
the noise.
The GX7 has considerably less of this problem at any given ISO than the
E-M5. Otherwise, the image IQ seems the same to me.
Do I assume correctly that the artifact is a permanent and irreparable
feature of increased ISO sensitivity?
If you mean can it be corrected once it has occurred, no. If you mean will it always be a feature of sensor systems, I
don't know. I haven't used one yet without it, from awful on some early compacts to relatively subtle. But that's not to
say all cameras have it.
I took a series of shots of a fixed target, using a tripod and macro lens, to compare noise and artifacts of E-M5 and
GX7. I didn't take notes, and the EXIF doesn't list a lens. I think it was the OM 80/4 Auto, but can't swear to it.
Here are 100% samples of the ISO 3200 shots.
<http://www.moosemystic.net/Gallery/tech/GX7/GX7vsE-M5_noise.htm>
With noise, the artifacts are far from obvious. Remove the noise, and lots of thin little lines appear. They look sorta
like scratches in the green, and more like marked lines in the red.
Flip back and forth, and you will see that they were there all the time. Go to
the GX7 image, and they aren't there.
I'm not sure anyone aside from a compulsive pixel peeper would notice them, especially at ISO 800 or below. They
certainly won't show up in any size print anyone here is likely to make. But they've always bugged me.
One might conclude, from this one sample, that the overall image detail is slightly better in the GX7. I'm not sure of
that, though, as very slight differences in focus, NR, etc. could also be a factor. I treat them as equivalent, other
than the 'worms'.
Interesting differences in color.
<http://www.moosemystic.net/Gallery/tech/GX7/GX7vsE-M5_noise.htm>
Wormed Moose
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