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03-30-2018, 06:57 PM   #1
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Problem with Pentax KP and smc da 50mm f/1.8 lens

I just got a new SMC DA 50mm from amazon and the auto-focus does not seem to work with my KP. It makes spinning noises but the focus ring does not spin and it does not auto focus at all. I tried the lens with my old K-50 and it seems to auto-focus OK. I also have a DA 18-135 and a DA 55-300 PLM and those both auto-focus just fine on the KP. Does anyone have any ideas? Thanks in advance.

03-30-2018, 07:09 PM   #2
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Check the AF drive shaft on the camera. Does it appear dislodged or recessed? If not, try wiggling the lens a little after mounting it to ensure that the gears engage. Also, try cycling the AF/MF switch, as it physically pushes the drive shaft out.

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03-31-2018, 05:45 AM   #3
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Do you have any other screw drive lenses? Both of your other lenses have internal motors and don't use the screw drive to focus.
04-02-2018, 06:00 PM   #4
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After wiggling it a bit it seems to be working...


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