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Hot Pixels


traveler11

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The majority of the pixel trails are in the top 2/3. Rik Littlefield of Zerene Systems says,

 

"During the stacking process, Zerene Stacker rescales and shifts images as necessary to keep the subject in one place, which then means that the white dot appears to move across the frame. Zerene Stacker treats the white dot(s) as detail to be retained, and so in the output you end up seeing the white dot in all of the various positions that it had across the whole set of source images."

 

I have identified 12 such errant pixel sites that bugs me no end.

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First of all, that is a really nice photo.

 

I think that there are threads in the M8/9 forums about hot pixels. I'm sure if you do a search for:

 

send dng file leica map out hot pixels

 

You'll get plenty results, perhaps even in the S forum. I think I've read somewhere that others sent in an S DNG file and Leica replied with a simple DIY fix.

 

Hope this helps.

 

BTW, why'd you use 80 ISO for this photo?

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The majority of the pixel trails are in the top 2/3. Rik Littlefield of Zerene Systems says,

 

"During the stacking process, Zerene Stacker rescales and shifts images as necessary to keep the subject in one place, which then means that the white dot appears to move across the frame. Zerene Stacker treats the white dot(s) as detail to be retained, and so in the output you end up seeing the white dot in all of the various positions that it had across the whole set of source images."

 

I have identified 12 such errant pixel sites that bugs me no end.

Thanks for your reply and your nice picture

Anyway, back to Wetzlar for HotPixels.

Send the crops of the regions concerned and the original photo

Regards

Henry

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  • 2 weeks later...

Received a reply from Leica the other day. Their request was to send the body to Wetzlar which I did, yesterday.

 

Rik Littlefield of Zerene Systems says:

 

 

Please examine your source images. I expect you'll find that each of the white dot trails in the output image corresponds to a single white dot at a fixed position in the input files. What happens is that as you step focus, the subject moves slightly across the sensor. During the stacking process, Zerene Stacker rescales and shifts images as necessary to keep the subject in one place, which then means that the white dot appears to move across the frame. Zerene Stacker treats the white dot(s) as detail to be retained, and so in the output you end up seeing the white dot in all of the various positions that it had across the whole set of source images. There is a similar situation with dust on the sensor, in which case you end up with "dust trails" of dark spots.

 

Now, as to the origin of the original white dots, those are typically due to "warm pixels". Warm pixels are individual photosites that happen to accumulate charge due to electrical leakage at a rate that is much faster than usual for the sensor. They typically appear only with long exposure times and are worse when the sensor is thermally warm due to hot weather and/or long periods of operation in live view mode. As a matter of routine practice, they can be reduced or eliminated by increasing the illumination level so that long exposures are not required.

 

Most sensors have a small number of warm pixel sites, and camera manufacturers normally do not consider them to be defects in the sense of something that warrants replacing the sensor. However, it may be necessary to update the "defect map" (or whatever Leica calls it) so that the camera and/or raw converter will know to ignore the warm pixel locations and instead fill in pixel values interpolated from nearby pixels that behave better.

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  • 4 weeks later...

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An update to my problem. Leica in Wetzlar received my S2P after a week and a half in customs. They acknowledged a defective sensor and will replace it at no charge. Most users might never see the problem I am experiencing, because seeing 1 random bad pixel is unlikely. My photo stacking against dark backgrounds exacerbates the problem.

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