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11-09-2010, 09:55 PM   #1
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K-7 magenta lines and bands

I'm getting ready to send back my second K-7 since this spring due to magenta lines showing up in the photos. I'm pretty sure it's a defective sensor. Has anyone else seen this kind of problem, am I just incredibly unlucky, or am I doing something wrong/stupid here?

I've got a few samples. These are chosen to emphasize the problem, so they're ISO1600+ and pushed in Lightroom. But I've seen it down to ISO400. Clickthrough for larger on all of them.

This is a sample from my first sensor:




Here are a few more from my replacement sensor.

Note the vertical line about 1/4 in from the left side of the frame. This is an uncropped shot. The line is always in that same place, but the other shots are cropped.


This is a cropped shot - the line is horizontal a bit below the centerline.


Wide horizontal band. Look across the bottom of her coat.


This one's a bit hard to see here, but it's a horizontal line. It's most visible a bit up and left from the centerpoint.


11-09-2010, 10:20 PM   #2
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Are these all shot with the same memory card? Just a shot in the dark, but maybe you have a bad card.
11-10-2010, 06:02 AM   #3
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The line is always in the same place? Sounds like a bad sensor.
11-10-2010, 09:12 AM   #4
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I'm 99% sure they're on different cards. I rotate through five separate 2GB cards, and I have examples spanning months, so it would be pretty surprising if they were all on the same card.

I think it is a bad sensor - last time I sent it in for repair they replaced the sensor. It just seems really odd that I would get two sensors defective in the exact same way, hence I'm wondering if anyone else has seen something like this.

Hm, perhaps there's some fault in the support electronics that fry the sensor after a while?

11-15-2010, 11:18 AM   #5
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When is the last time you updated your firmware?

11-15-2010, 11:18 AM   #6
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See my response to your inquiry here.
https://www.pentaxforums.com/forums/pentax-dslr-discussion/118861-k-7-defecti...ml#post1258874
11-15-2010, 11:22 AM   #7
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It was the v1.10 firmware, which is still the latest. I jumped on that as soon as I could, because I like using the electronic level and being able to see the exposure meter at the same time.
11-15-2010, 11:29 AM   #8
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Other than agreeing with the rest of the posters, I'm out of ideas. I think the camera is still worth fixing for whatever that's worth.



11-15-2010, 11:32 AM   #9
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Yeah, I'm sending it in for repair today. I was mostly curious if anyone else had seen it. Also, now it's out there on the intertubes in case someone in the future runs into the same problem.
11-15-2010, 07:11 PM   #10
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Do you do any long term use of live view or shoot a lot of video? It could be thermal damage to the sensor if the overtemp protection isn't shutting the camera down as it should.
11-15-2010, 07:17 PM   #11
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I've shot a total of maybe 2 minutes of video with it. I use Live View a fair bit for focusing when on the tripod, but I don't think excessively so. I'm not terribly in love with the LCD.
11-15-2010, 07:34 PM   #12
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QuoteOriginally posted by breischl Quote
I've shot a total of maybe 2 minutes of video with it. I use Live View a fair bit for focusing when on the tripod, but I don't think excessively so. I'm not terribly in love with the LCD.
Sorry to say, I think you're a statistical outlier! For your benefit, I'm hoping the third sensor is a charm. Good luck with the repair.
11-15-2010, 09:20 PM   #13
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One could be a tad cynical

and suspect that your original defective sensor was not actually replaced - maybe someone they had "fixed" it and merely said they had replaced it. It would be interesting if you could compare the banding from the two sensors if they occupy the same pixels ...
11-15-2010, 09:26 PM   #14
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Heh, well, I suppose that could be the case... I'd like to give the repair shop the benefit of the doubt, especially since I just mailed the camera to them again.

I think they must've done something, as the line was in a different place before the repair than it was after. But aside from that, it was very consistent - all the photos from "before" have it in a consistent place. In the shots from "after" it's equally consistent, but in a different place.

Full frame "before":


Full frame "after":
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