D7100 'streaking'

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

Jack Hogan wrote:

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.

I presume that NEF files were shot with ADL in-camera enabled. (I forgot its canonic Nikon name). We cannot exclude it because it is already in NEF file. Nikon had 2 type of ADL, one simple as postprogram, such as in d3000 camera at least. Another is in senior cameras as in D300s, which involved data reading from chip.)

then RAW compression defines which data will cut

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

I mean compressian of data to be 12-bit wide, which are image specific. No

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.

No-no-no. Nikon do it in all cameras beginning from D200 or maybe from early beginning. But here at d7100 sample we found visual bug in these program code $)

But VERY IMPORTANT DISCOVERY:

Until ISO400 we presumable have clear raw data,

Yet streaking is visible at ISO100 without pushing

So at ISO 100-400 we have one data conversion path, but from ISO 800 image data gets another way...

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?

You've already seen it on pictures. From these samples I conclude that these stripe artifacts are no lens defect, no photosites overloading, no sensor errors but round error in data calculations.

Jack

You, Jack, talk about RAW conversion software, but I talk about preprocesses before writing NEF.

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