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08-09-2009, 04:02 AM   #1
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Dead pixels?

I was taking some photos at night last night and ALL of them seemend to have a dead pixel.

So this morning i took 2 pictures in pitch black with 2 different lenses and seemed to get a "dead" pixel in the same areas, the photos looked identical.

http://i302.photobucket.com/albums/nn100/Crooks3y/dead_1.jpg

http://i302.photobucket.com/albums/nn100/Crooks3y/dead_2.jpg

Is this right, should this happen in low light?

Camera fault? Ive only had it a few weeks (from new) so its still under warranty if it needs to be repaired / replaced.

I would appreciate any comments / suggestions

08-09-2009, 06:30 AM   #2
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Maybe can try the sensor pixel mapping function to get rid of them?
08-09-2009, 07:40 AM   #3
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when I first got my k100D, I found the "dead pixel" problem when the JPEG file is viewed at 400%, the pixel appears as "+". It does not appear in RAW image.

Pentax repair shop fixed that problem using pixel remapping when my k100D was still under warranty.
08-09-2009, 08:44 AM   #4
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Pixel re-map it yourself via the camera menu. I had the same problem recently and just fixed it up via the camera menu.

With gazillions of pixels on your sensor there's always going to be a few dud or hot ones at random locations. Even expensive camera's suffer from it.

When the dead pixels form visible clumps or form a long straight line or something, then it is time for a sensor replacement. Had that issue once with a Fuji FinePix F10 point and shoot. Sensor replacement under warranty was the only solution then.

08-09-2009, 01:59 PM   #5
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You don't say what model you have; the suggestion to run the pixel mapping feature is relevant only the for the models that have it (K200D, K20D, K-7; not sure about K-m; I don't think any others do).

But if it only shows up in long exposures, I wouldn't bother - it's totally normal for a few otherwise good pixels to exhibit problems with long exposures due to the sensor overheating. Most RAW software can eliminate those for you, and if you have the Slow Shutter Speed NR custom option turned on (relevant to all mdoesl except K20D and maybe K-7), the camera may also remove them for you.

If they show up all the time, it is again normal, and not really worth sending the camera in for until you've got so many you can't stand it, as more do develop over time.
08-09-2009, 02:14 PM   #6
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Dead pixels happen all the time in cameras. Sometimes a pixel will misfire and sometimes it won't.
08-10-2009, 03:13 PM   #7
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I do see some on mine but only when I view it full size, otherwise, I just leave it and pay no attention to it as I know the K100D super doesn't have the pixel mapping feature too.
08-10-2009, 07:33 PM   #8
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As an aside, I was surprised to read in the dpreview Nikon forums that many new Nikon's - eg the D90 - don't have any in-camera pixel mapping function.

With the D90 if you find a hot pixel or two you have to send the camera back to a Nikon service centre to get it re-mapped. The dpreview forum is full of people sending their D90's back to Nikon over finding 1 or 2 dead pixels, then waiting a week or two for the 'repair', then finding another dead pixel in a month or so, and repeating the procedure....

Score +1 for Pentax here, at least I guess for models K20/K200 and newer. Newer Olympus apparently also support pixel remap I believe.

08-10-2009, 08:17 PM   #9
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I had a red colored bad pixel showing up intermittently in the same spot in my photos. I used pixel mapping and it's gone. The only headache now is to take the little red dot out of all the shots that have it. Luckily, they are all RAW rather than JPG's. I only have the Pentax RAW software that came with the camera. Does anyone know if there is a batch pixel remove feature I can utilize to take it out of every pic, so I don't have to do this one by one?
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