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01-04-2012, 12:18 PM   #16
ogl
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Sorry, I will make some tests soon...I was too busy.

01-04-2012, 02:17 PM   #17
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QuoteOriginally posted by ogl Quote
Sorry, I will make some tests soon...I was too busy.
If this is a raw processing bug, the way to confirm that would be to use another raw processor like DCU4, or probably better because it does no optimisations, RawTherapee.

As regards how ISO80 is achieved, I can't think of a reason why that would affect resolution. I speculate that the linearity of the sensel deteriorates near FWC. Nikon & Sony do not run it in this region. Pentax does, and compensates for this non-linearity in their processing. Hence they can push the FWC a little further.

Or maybe Pentax has mapped the gain of each sensel on each individual sensor and compensates for these PRNU irregularities. (Probably too expensive to do this though in a non-pro camera.) This would give less highlight noise at base ISO. Perhaps this would somehow allow a better FWC too.

Dan.

Last edited by dosdan; 01-04-2012 at 04:02 PM.
01-05-2012, 08:02 AM   #18
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QuoteOriginally posted by dosdan Quote
I speculate that the linearity of the sensel deteriorates near FWC. Nikon & Sony do not run it in this region. Pentax does, and compensates for this non-linearity in their processing.
Dan, interesting idea.

However, I'm not sure this is compatible with the part as Sony ships it. It delivers the raw image data in digital form and AFAIK all you can do is program a 4 bit digital amplification factor prior to ADC. All else is in-camera post-processing. The 4 bit factor means 1 ... 31 actually but I'm not sure it can go above 16.

So, it's the same game for everybody.

To avoid to expose near the FWC, you really have to underexpose. But this would be renormalized by DxO if the camera would do so. So, I'm rather sure that FWC is not involved in the Pentax ISO 80 (or 14+EV DR) conundrum.
01-06-2012, 06:43 AM   #19
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Hmmm...I've found today that my FA43 is unpredictable at K-5....Big problem with AF accurancy, not with sharpness. I will retest with FA77 or FA135. It's much better than FA43.

01-08-2012, 11:15 AM   #20
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QuoteOriginally posted by ogl Quote
Big problem with AF accurancy, not with sharpness.
I would have guessed that you were aware that AF accuracy is the #1 issue to check with sharpness tests.
01-26-2012, 02:23 AM   #21
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No any difference with ISO80 and ISO100
01-26-2012, 02:35 AM   #22
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There is going to be very little discernible difference between 80 and 100. But there are early sources that note 80 performing very well in every aspect, particularly shadow detail. No issue with sharpness. Each camera may have its AF accuracy nuances but it's not an ISO 80 issue.
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