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Old Jan 8, 2012, 9:17 AM   #1
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Default K5 Dust or Stain

Having just owned the K5 for a mere 2 weeks, I've noticed dust specks on recent shots, The Dust Alert check didn't show any and using a Rocket Blower appears to have dislodged all but one which despite several attempts at 'electronically' cleaning & blowing, it still persists.

I've yet to return it to the dealer, but do you think that because it doesn't show up using the Dust Alert process, it could be a stain on the sensor.
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Old Jan 8, 2012, 11:25 AM   #2
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There are no stains being reported from recently produced cameras (because the stains were an issue with the first batch(s) of K5s where Sony and then Pentax both failed to spot the stains. It shouldn't have occurred since then however there are some unscrupulous dealers / sellers who maybe didn't return / fix the issue and continued to sell 'stained' K5s ... so the fist thing to do is check the production date of your camera (EXIF).

Shoot a picture of a white wall at f22 for 5 seconds and see if the stain is present ... if not then it isn't a stain.

Your problem definitely just sounds like dust and even the best rocket blower can sometimes fail to dislodge 'stubborn' dust. In these cases the sensor may require a 'wet' clean. Careful there though.
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Old Jan 8, 2012, 11:11 PM   #3
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Post a picture. I had stains on my first K5, and it's quite a bit different than dust, even the dust you can't dislodge well. What's the manufacture date of your camera?
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Old Jan 9, 2012, 11:49 AM   #4
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The attached image is a section from the top left corner of the overall image. Given the initial spread, I was suspicious that it could be staining but having removed all but the bottom right speck, it's pretty safe to assume that it's dust. It's gone back to the dealer for cleaning, so I'm hopefull that all will be well.

Date of manufacture is October 2011, so it's quite a new build & unlikely to be stains unless, of course, there's a fault on the sensor.
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Old Jan 9, 2012, 11:54 AM   #5
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It's dust .. but for future reference if checking for stains you need to follow the procedure I gave above. In normal use you'd never see the stains (they aren't that big as those in your pic !) unless you were shooting at F11 or above or possibly on long exposures.
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Old Jan 9, 2012, 3:14 PM   #6
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Definitely not anything like the stains I had on my first K5 - they do look suspiciously like a dust-spot I have on my current camera.

I somewhat disagree about not seeing stains in normal use. I first noticed mine when using a small aperture (I think about f14 or so), trying for some optical illusion. I went back to see where they started to appear (I had checked the camera when I bought it and again after about a month and there weren't any stains), and discovered that I could see them at f5.6 though they weren't obvious unless there was sky at that spot, and rthat they had only been there for about a week or two.
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Old Jan 9, 2012, 3:17 PM   #7
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According to the dealer, he's been unable to remove ALL dust despite repeated attempts & has concluded that the mark must be between the sensor & the filter.

I've requested a replacement as I've only had the camera just over 2 weeks.
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Old Jan 9, 2012, 10:39 PM   #8
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Sounds good to me - great to have a nice dealer like that.

Here's a 100% crop of the stain that I had on my camera - it's what was typical of the stains on the early K5 cameras.
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Old Jan 9, 2012, 11:13 PM   #9
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Yes, Harriet's is the very typical 'string of pearls' stain.
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