D7100 'streaking'

Started Apr 7, 2013 | Discussions thread
Jack Hogan
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Re: D7100 'streaking' - doesn't look like blooming or flare
In reply to krikman, Apr 9, 2013

krikman wrote:

Some reasoning:

ADR algorhytm works with native data (in 14-bit space?) by somehow analysing of large blocks of data,

If you mean ADL, we can exclude it as the culprit because I see streaking in RawTherapee and RawDigger which do not do ADL.

then RAW compression defines which data will cut

Raw compression is just a lookup table, no intelligence/definition involved

in conversion to 12-bit, but coders forgot to cut unusable bits from precise calculations so we got rounding error in green channel.

(i.e. pixel has value 10100011, we cut last 2 binary digits '11' but they appear in each and every cell in row and add regular 0,5% for whole row)

I doubt that Nikon would do this differently in the D7100 than in the D800 or that it would depend on whether part of the line is much brighter than another part.

But VERY IMPORTANT DISCOVERY:

Until ISO400 we presumable have clear raw data,

Yet streaking is visible at ISO100 without pushing

but from ISO800 Nikon 'cooks' RAW data by different datapath with intensive onchip (?) NR. It is common sense but first time we had clear instrumental proving.

Can you provide details on your analysis and the data to support your claim?

Jack

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