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03-13-2016, 03:11 PM   #1
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K50 metering issues

I am having some issues with the metering on my K50. It is severely underexposing photos when using the viewfinder. It still seems a bit off when I switch to live view but the exposure is at least pretty close. I made sure the exposure comp is at zero and tried a few different lenses but ended up with the same result. I also tried switching metering modes and shooting in a variety of modes (aperture priority, shutter speed priority, manual) without any effect. On an older k series lens I tried out, I also noticed the green button no longer works for stop down metering. My best guess is that something is wrong with the aperture control in the camera. Would that make sense/ any other ideas?
Thanks in advance for any help

03-13-2016, 04:38 PM   #2
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This sounds like the same issue that several other owners of high-mileage/-age K-30 and K-50 owners are experiencing. If you can't achieve a proper exposure even in manual mode, I'd get the camera serviced, or replace it.

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03-13-2016, 05:04 PM   #3
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Unfortunately it sounds like your guess is correct - the aperture control mechanism seems to be on it's way out. I'm surprised by how many threads I've seen recently of people having this issue. Not very promising for newcomers to Pentax or potential K-50 buyers.

Try what this forum member suggested to test whether or not it is the aperture control mechanism:

QuoteOriginally posted by stevebrot Quote
Welcome to the Pentax Forums. This sort of problem has been reported in the past. Do this simple test to confirm that the aperture mechanism is functioning properly:
  • M mode using optical viewfinder (live view off)
  • Shutter speed at 3 seconds
  • Aperture at maximum for the lens mounted
  • While looking into the lens from the front press the shutter release
  • Confirm that the lens stays wide open during the exposure
If the lens stops down, there is a fault with the aperture actuator mechanism. This is repairable and is covered if the camera is still under warranty.


If it is the aperture control mechanism, try this to get it working:
  • Do burst shots by turning on Continuous Shooting so that the aperture changes every shot.
  • Make sure to turn off AE-L. Set the camera to JPEG just so that it's quicker.
  • Do this indoors with the light on. If using a prime, point the camera at the light, then away from it, then at it again, then away from it - point is to have the aperture change every shot. It could be whole, half, or third stops, as long as it changes to 3 different f stops.
  • Or use a variable aperture zoom and set it to the widest aperture and quickly zoom in and out so the aperture changes. Again try to have it change to at least 3 different f stops.
  • Lastly do this on a fully charged or almost full battery otherwise you will need to take more shots to get it working.

Doing this may wake up the aperture control mechanism and get it back to working normally. But this is temporary and it will stop working again, can be within a month, week, day, or even if you turn the camera off or don't use it for 10-15 minutes or so (might be sooner or later depending on the degree to which the aperture control mechanism is malfunctioning). I don't know if this trick would eventually stop working, but If your camera is out of warranty you'll still be able to use it.
03-13-2016, 05:51 PM   #4
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Gave it a try and it was stopping down. Couldn't get it unstuck with the burst. Conveniently they threw in an extra two year warranty when I bought it so I'm still in luck. Thanks for the help.

03-13-2016, 06:05 PM   #5
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QuoteOriginally posted by Adam Quote
This sounds like the same issue that several other owners of high-mileage K-30 and K-50 owners are experiencing.
Many users, but not all high mileage. Some cameras have had very low shutter counts.

03-13-2016, 06:53 PM   #6
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Some of you may have seen my post from last week with the same issue. I had less than 12,000 on my k50. Wouldn't say it's high mileage but also not new. It lasted two years to the month. But it was a good excuse to get a k3 which I love btw.
03-23-2016, 05:57 AM   #7
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Mine lasted for just under 2 years before the problem popped up. SC was under 4600 when it appeared.


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