D7100 'streaking'

Started Apr 7, 2013 | Discussions thread
Jack Hogan
Senior MemberPosts: 3,943Gear list
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Streaking = Smart IQ
In reply to _sem_, Apr 10, 2013

_sem_ wrote:

Horshack wrote:

Here are two exposures, 1EV apart, shot at both ISO 100 and 200. The lower exposure is much worse, indicating it is something with the shadow+channel balancing/black clipping for rows which also have saturated pixels

I think in the higher exposure there's streaking in both the top and the bottom half, with, just a few lines left out below. But in the lower exposure, there is full streaking save a few lines above, and much leass streaking below, therefore the "contrast".

Right.  I can see it easily without any push in the OP's original ISO 100 NEF, where the highest value in the Green Raw channel was 935/4095, virtually guaranteeing that neither photosites nor the ADC were anywhere near saturation, pointing the finger squarely at pre-Raw processing.

As Moss says, this could be caused by row-customized offsets and linearizations, such as black level subtraction, WB preconditioning or who knows what else (where's Iliah Borg when we need him :-)).  The D7100, like its little brother the D5200, plays with the pre-Raw data more apparently than most.

However, as interested as I am in understanding what's going on under the hood, if that's what they are those operations are pretty smart and actually benefit the IQ of captured images in most situations.  The fact that we can see their effects in extreme tests such as this shouldn't detract from our enjoyment of what appears at the moment to be the best APS-C sensor out there.

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