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08-06-2019, 02:34 PM   #1
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Pentax FA 50 f1.4 autofocus?

Hi all

Apologies if this is an absurd question as Iím a bit of a noob to Pentax.

Iíve gone a little lens wild and bought via eBay an FA 50mm f1.4 and noticed in the reviews here that itís autofocus through a screw...

I have a Pentax KP and have no idea how to get my lens to autofocus. Iíve switched on the AF and nothing. On the camera the F value is flashing as it canít pick it up from the dial.

Am I trying to get it to do something it canít?

Thank you in anticipation!!


08-06-2019, 02:39 PM - 1 Like   #2
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BigMackCam's Avatar

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Hello and welcome to the forums

It sounds as if the camera isn't communicating properly with the lens. Assuming your other AF lenses are working fine with the camera, clean the lens' electrical contacts and the mount ring, then re-mount the lens and try again.

Let us know how you get on?
08-06-2019, 02:43 PM - 1 Like   #3
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Make sure the lens is in the 'A' position on the aperture ring.

And no, you are not trying to do something the lens cannot do. It should function and autofocus on your camera with no issues if it is set up correctly.
08-06-2019, 02:53 PM - 1 Like   #4
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Make sure you push the little button on the aperture ring when setting it to A.

If it still doesn't work when set to the A position you might have to clean the contacts on the lens.

08-06-2019, 03:13 PM   #5
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Thank you!

My camera is at work so as soon as I get in tomorrow Iíll be checking out that A! I hadnít noticed it today.
08-06-2019, 03:22 PM - 1 Like   #6

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Hi Drtimvp


You have to set in menu Aperature Permitted then all should be fine
I do not have a KP but it will be in the manual as to where
And the "A' setting on lens aswell

08-07-2019, 03:49 AM   #7
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Thanks all!

I now have a functioning lens - canít believe I didnít spot the ďAĒ. Bought a brand new sigma 70-210 f4-5.6 from a charity shop for £14 and thatís now working too!

Very appreciated.

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