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dead pixel on M 240


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I purchased a M 240 at Samy's in LA. I noticed several dead pixels at certain iso range so I exchanged with the new one today. I carefully examined some images(donno why I did that) and found one dead pixel visible when magnified 100%. I understand that there is no perfect sensor and am trying to ignore it because it doesn't show up once the dng file is processed. Hope Leica includes a remapping software in the next firmware update.

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  • 1 month later...
Check it at ISO640. Some dead pixels cause a dead line at that ISO. Must then be fixed by Leica.

 

Just noticed dead column, got the impression it happens randomly but at closer examination it appears regularly at ISO 640. OK, know now how to avoid it but does anyone can provide explanation why at one specific ISO setting & is it going to get worse.

 

So, remedy is trip to Wetzlar, it is going to be slow with holiday season in full swing, it seems auto ISO will have to wait until this is fixed.

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Is there a specific way to shoot the test image? Because here's what I found: I took 2 shots @ ISO 640, jpeg-fine. One with the lens cap on at 1 sec. Another of an off-white wall, 50/1.4 @ 1.4 on A. In the lens cap on image, when I zoomed all the way on the camera's LCD it was a bright blue screen flashing, and there were tons of little black dots scattered everywhere (some in a vertical row but not a continouous line). When I imported that image into LR and viewed it at 100% I scanned it all over and could find nothing, it was totally black. With the shot of the door, in LR @ 100% I found one light-blue dot over to the left.

 

So am I not doing it right or do I have just that one lone dead pixel?

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Is there a specific way to shoot the test image? Because here's what I found: I took 2 shots @ ISO 640, jpeg-fine. One with the lens cap on at 1 sec. Another of an off-white wall, 50/1.4 @ 1.4 on A. In the lens cap on image, when I zoomed all the way on the camera's LCD it was a bright blue screen flashing, and there were tons of little black dots scattered everywhere (some in a vertical row but not a continouous line). When I imported that image into LR and viewed it at 100% I scanned it all over and could find nothing, it was totally black. With the shot of the door, in LR @ 100% I found one light-blue dot over to the left.

 

So am I not doing it right or do I have just that one lone dead pixel?

 

Try just taking a slightly underexposed shot of a plain blue sky. That worked for me and easily showed up a dead line at ISO640. I shot in RAW + JPEG but I'm guessing JPEG fine would work too. Also I wouldn't bother reviewing it on the LCD, it is identifiable but only if you zoom right in and track left to right until you come across it. It's so much easier to check it in Lightroom where you will see it in an instant.

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I was looking for any pixel issues that might be significant enough to warrant repair.

 

I shot the homogenous off-white door in "A" so naturally it was underexposed about 1-1.5 stops. So I guess that one pixel is it so far.

 

The reason I shot jpeg to test was because I keep reading LR automatically maps out dead pixels from DNG's.

 

But I recall something about testing for pixels by taking a shot with the lens cap on. Maybe that's for hot/stuck pixels, not dead ones. That would make sense I guess.

Edited by bocaburger
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If Lightroom maps it out, then just don't worry about it. When you get the blue line prone\blem, send in your camera. You will drive yourself nuts, if you worry about pixels that get corrected automatically.

 

Lightroom only maps out pixels if I shoot DNG, which I prefer not to do. So far the M240's jpgs have been remarkably pleasing. However the one dead pixel I was able to find is off in the lower left, about 10% up from the bottom and 20% in. In the rare instance it might actually impact a photo, it ought to be simple to clone it out in one click.

 

And the reason I was testing is because my camera is <30 days and if it had a dead line I would press the dealer to collect it and exchange it rather than send it off @ my expense for Leica to take who knows how long repairing it.

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I just quick examined mine, and found one. I am afraid what it will look like tomorrow when I get the blue sky available. :-)

I didn't notice it before as I wasn't aware LR was automatically correcting it. As I started to use C1, the feature is gone so I'd like some fw option from Leica too, yet don't see it in any near future. The only problem is the pixel is close to the center of the frame.

 

The photo is 11:1, but I can also see it on 1:2 on my 27" monitor.

 

...I found four more. The funny thing is two were blue, one white, and one kind of beige. :D

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Edited by mirekti
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  • 1 year later...

Well, it's been some time since the last post :)
In the mean time I let the LR do its job in hot pixel removal, but few days back I found another issue. 
This time LR does not help as I'd presume this is not a hot pixel but something else. 
If you check the image you can see that the burned out area looks like a bit of dust not like a single square pixel. 
Does anyone have an idea what this might be?

 

UPDATE: I did the same test as in 2014 by increasing it to 11:1. It seems as a bunch of hot pixels. :(

Is there a way to tell LR which pixels are dead or do some trick to fix this automatically during the import?

Option 2: Would it be possible to send a DNG with the lens cap on to Leica and they provide me with a file (similar to FW) which would do the remapping of these pixels or the camera would have to hit the road for this to be fixed?

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Edited by mirekti
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Well, I will not send a three year old camera for a repair. Certainly not for a sensor which is a thing that was outdated even before it was released in the camera (in general, not only with Leica). 

I can live with it. If you check the whole picture it's not so huge, but it would be great if Leica provided an online service for pixel remapping/fix. I don't understand why this would need to go for a repair service. ...unless they want to charge something extra for it (even then it should be possible to fix it online). 

 

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Edited by mirekti
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Why not? There is a good chance that it will be fixed for free. For a new sensor there is always a number of pixels mapped out. If the number of pixels to be mapped out reaches a certain value the sensor will be replaced - that goes for all brands of camera.

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