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03-10-2010, 09:40 PM   #1
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What counts as a dead pixel?

I have noticed many weak or dead/hot pixels on my new K-7.

What is the definition of dead/hot?

Does weak count?

I have 45 noticeable or obvious pixels that are showing.

03-10-2010, 10:09 PM   #2
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Dead pixel = pixel that won't light up.

'hot' or 'stuck' pixel = a pixel that stays lit in a certain colour and won't change.

The way i test for stuck pixels: turn on live view, put camera at iso100. Point camera at something bright, lock exposure. put lens cap on, look at screen and snap a picture. If you see any obvious super bright spots of colour in the live view screen or in the photo, you have hot pixels.

Update your firmware and run pixel mapping. I had a bunch of stuck pixels in my new k-7, but then i updated the firmware and it was fine.
03-10-2010, 10:43 PM   #3
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yeah, the pixel mapping feature works well. I've used it and now I see no stuck or hot pixels anywhere, even during long exposures.
03-11-2010, 10:24 AM   #4
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QuoteOriginally posted by GoremanX Quote
yeah, the pixel mapping feature works well. I've used it and now I see no stuck or hot pixels anywhere, even during long exposures.
I am updated to 1.03 and yeah I can use that mapping feature but @ ISO 1600 with lens capped and covered a 2 second exposure giving me 45 dim to bright pixels seems pretty extreme to hide doesn't it or am I just expecting to much from my K-7?

03-11-2010, 10:34 AM   #5
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Pixel mapping feature or not I would be sending a camera with 45 dead/hot pixels straight back to where it came from.
03-11-2010, 10:41 AM   #6
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QuoteOriginally posted by Mike.P Quote
Pixel mapping feature or not I would be sending a camera with 45 dead/hot pixels straight back to where it came from.
That's kinda what I was thinking but wanted to make sure that even though some are very dim and barely visible (100% peeping) and come in white, red, blue and green and occur repeatedly in various test pictures that I wasn't just over exaggerating.

The worst thing is that I had already had the first one sent in and replaced for focusing issues and that used up a good chunk of my 30 Amazon days and then had to send in the UPC code from the box for the $100 rebate. Now I am stuck with losing it for 30-45 days for repairs and I fear that since I am seeing one story after another on here and elsewhere that people sending in for repairs with the K-7 and K-x are getting them back worse off and with new problems and sometimes the original problem is even still there.

Last edited by KansasHorizons.com; 03-11-2010 at 10:47 AM.
03-11-2010, 12:30 PM   #7
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QuoteOriginally posted by KansasHorizons.com Quote
I am updated to 1.03 and yeah I can use that mapping feature but @ ISO 1600 with lens capped and covered a 2 second exposure giving me 45 dim to bright pixels seems pretty extreme to hide doesn't it or am I just expecting to much from my K-7?
I dunno, let's see:

45 dead pixels divided by 14,200,000 total pixels equals...

damn, my calculator can't display such a tiny number in a readable format.

So no, I don't think it's that bad. Honestly, there are probably more than that on your sensor. Pentax does Pixel Mapping from the factory before the camera gets shipped out. I wouldn't be surprised to learn that most CMOS-based DSLR's have more than 45 dead pixels. Technically, the Bayer array means your camera is doing full pixel mapping all the time anyways, that's just part of normal image processing. Those 45 pixels don't matter one bit once they've been mapped.

Now if they're really blatant even after you've done pixel mapping, there could be a problem.
03-11-2010, 01:27 PM   #8
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QuoteOriginally posted by GoremanX Quote
Now if they're really blatant even after you've done pixel mapping, there could be a problem.
That's my next step I suppose.

That left me with just a pair that were quickly noticeable and they are new ones that weren't there before. :ugh:


Last edited by KansasHorizons.com; 03-11-2010 at 01:51 PM.
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