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10-09-2010, 08:28 AM   #1
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Pentax A 50mm f1.2 lazy aperture problem

Dear All,

I`d like your kind advice about fixing "lazy aperture" problem on my A 50 f1.2. The aperture closes too slowly when you fiddle with the lever, and it shows when taking pictures - overexposures, etc.

Usually there are two causes of this: sticky aperture blades and weak or misplaced spring. I think I have the second one because when looking at the blades carefully I`m sure they`re super clean.

Can someone offer me advice or maybe service manual for the lens, so I at least know how to begin fixing this, from the mount side or front side of the lens.

Also there is always possibility to bring it in for repair by local Pentax service-center.

10-09-2010, 10:56 AM   #2
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Often you can't see oil on the aperture blades, but that is what I suspect is the problem with yours.
Any shop competent with camera lens repair should be able to repair yours quickly and cheaply.

10-09-2010, 07:59 PM   #3
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They are probably all put together about the same way.. This May help..

password is Pentax


Pentax Manuals

10-10-2010, 09:17 AM   #4
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I had the same problem with my K20/4. It sent it to Eric for a CLA and it was oil on the blades. After the CLA all is well!


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