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10-25-2014, 06:17 AM   #1
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K50 Strange Mark on Images

So my k50 is about 2 months old. While taking some snaps with a clear blue sky, I noticed this strange mark. It appears on all images, but not really noticeable if not in a clear sky. Could have been there since day 1 but I can't find any earlier shots with that clear of a sky.

Not the lens issue since I tried different lenses. I also did a test using raw and it also shows there. Upgraded the firmware to 1.02. no difference.

Any ideas would be appreciated or do I just send it in for repair.



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10-25-2014, 06:24 AM   #2
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Dust inside your camera. You need to clean something. What depends on where the dust has ended up.
10-25-2014, 07:00 AM   #3
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Yep, dust speck on the sensor. It happens. It's not a big deal. Looks like some sort of fiber, so it probably won't be too 'sticky'. You can google "dust on sensor", but here's the procedure in short:

1) Get some sort of air puffer (NOT canned air - that can spray oils and propellant). Google 'giotto rocket' to see what I mean.
2) Put a fully charged battery in the camera. In a not-too-dusty room, remove the lens, and turn the camera on. Try to keep the camera pointing down, so no new dust falls into the body.
3) Find the menu entry for Sensor Cleaning. I think it's wrench-icon, tab 3. Select "Mirror Up". You will hear the shutter open.
4) Puff air onto the sensor. Don't try to touch the sensor, and don't stick the puffer so far in that it touches the sensor. Again, try to keep the camera pointing down, so the dust falls OUT of the body.
5) Turn the camera off, and remount the lens.

If you haven't enabled dust removal on startup and shutdown, you might want to do that.
10-25-2014, 07:08 AM   #4

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The little dust specks become more visible as the aperture is stopped down,after cleaning put the lens on(wide angle lenses seem to show the dust better) and set the aperture to f/16 or f/22 and take a photo of the sky.Any spots you might have missed should show up with this test.

10-25-2014, 07:28 AM   #5
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Dust on sensor. To remove it, try (in order):
  • In-camera dust removal system (sensor shaker)
  • Sensor clean using rocket-type blower
  • Sensor clean using available kits (brush, sticky pop, wet)
  • Professional sensor clean
Your user manual has the instructions on how to do the dust removal and sensor clean. The internal dust removal often does the job quite nicely and a blower usually works. I have been using a Pentax dSLR for over seven years and have never needed anything beyond a rocket blower.

Note: Do not use canned or compressed air!

10-25-2014, 07:30 AM   #6
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Well I didn't think about a dusty sensor with the camera being so new, but following THoog's excellent instruction a couple of blasts from the giotto rocket did the trick. Took some test shots at f22 and all looks good now.

Thanks to all for the help.

10-25-2014, 07:52 AM   #7

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Electronics are like a magnet for attracting dust,all you can do is be careful about where you change lenses and do so as quick as possible.Also make sure the lens you are installing is clean,any dust here can end up on the sensor.I'd say everyone with a DSLR is going to experience this no matter how careful they are but you can minimize how often the sensor needs cleaning.
10-26-2014, 05:35 AM   #8
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Same happened to my K30, it was less then 2 months old and I got a nasty spot. I don't have other lens other then the kit, so I never took out the kit lens. I tried first the dust removal option from the menu, but no luck, I had to manually remove it. I have no idea how it got in, maybe it was already inside from the factory...


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