M246 Hot pixels

[nscali]

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I have noticed when viewing my DNG files in Capture One or Lightroom that I see some small white 'hot pixels' in dark shadow areas of the image.

I can only see them zoomed at 100% on screen.

They are very small and are very isolated, with only a few appearing on very dark shades on th file.

I originally thought It was dust on the lens but they seem like hot pixels.

When I zoom the files on the cameras LCD I can't find them so I am not sure if the issue is DNG conversion or an issue on the sensor.

Again, they are few, small and only in the dark areas.

Has anyone encountered this issue before.

Many thanks

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[Akaki]

I thing you have not correct expose, then the sensor is react like this.

did you have in all your files? also where you have an ideal dng?

[jaapv]

Exposure time? ISO? Image?

[nscali]

It happens as low as iso 320, then at all speeds, exposures from 1/50 and up.

there seems to be about 3 white pixels on the image, always in the same location, regardless of which image. They are noticeable when you reduce noise reduction.

Sometimes they are invisible due to the subject or background brightness.

Naturally they are more obvious in dark backgrounds

[Joakim]

As far as I understand it hot pixels comes and goes away on a sensor so there is no point in trying to map them out since it's a temporary issue and if they come back it might be in completely different place on the sensor.

 

And if 3 out of 24,000,000 pixels are hot it isn't a major concern   

[nscali]

I didn't realise that hot pixels come and go. Is that right?

That makes me feel a bit better because it is such an expensive camera and it frustrates me if it doesn't work correctly.

I just love the IQ that comes out of it. 

[John Black]

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Hot pixels will be more of an issue in the summer than the winter.  They'll also crop more during long exposures and/or with continuous exposures.  LV / EVF usage will heat up the sensor too, so that's a consideration as well.  The common theme being - heat.  The warmer the temps get (whether sensor temp and/or ambient), the more likely hot pixels will show themselves.  

 

As a workaround, in Capture One go to the Noise Reduction palette and play with "Single Pixel" noise reduction.  It will filter out the hot / dead pixels.  It may or may not work because it depends whether C1 perceives the offending pixels as "hot" pixels or not.  Sharpening levels can exasperate hot pixel visibility by creating halos around them, so tinkering sharpness settings is another variable to experiment with.

 

My $.02 on this - if the offending hot pixels are always visible at base ISO no matter what the shooting conditions / scenario, I send the camera to Leica to get the pixels mapped out.  If the hot pixels only show on occasion at higher ISOs, then I roll with it and deal with them in post.  It's a pain sending the camera to Leica, but I have a low tolerance for stuck pixels if they effect every image.