70-210 F4 FA autofocus problems

jazzguy12 · 07-09-2022, 12:51 PM

I have the Pentax 70-210 f4 FA and love it. On my last trip the auto focus stopped working, manual focus still works. On the cameras (K-1 M II & K3 M III) screen says MF no matter how I have the AF switch on the lens positioned? Any help would be appreciated!! Thanks.

kypfer · 07-09-2022, 03:05 PM

Dirty contacts would be first choice, specifically the one nearest the auto-focus drive (most clockwise, looking at the back of the lens), or just possibly a sticky corresponding contact on the camera. The camera contacts are sprung loaded, it's not impossible for one to get jammed in a depressed position.

jazzguy12 · 07-09-2022, 11:45 PM

Must be internal, cleaned contacts, & checked to see if it would bounce back (the contact), it did.

**Michail_P** · 07-10-2022, 12:22 AM

The MF indicator most probably means dirty contacts.

biz-engineer · 07-10-2022, 02:58 AM

Check focus limiter position. On mine I sometimes hit the focus limiter unintentionally the lens won't focus unless I move that button back into place.

**mlag** · 07-10-2022, 07:53 AM

Originally posted by jazzguy12

..... the AF switch on the lens positioned?

On the lens, ok. But did you check also the AF/MF switch on the body?
Maybe re-apply if the switch is slightly out of position...

07-09-2022, 12:51 PM	#1
jazzguy12 New Member Join Date: Apr 2014 Location: santa cruz Posts: 2	70-210 F4 FA autofocus problems I have the Pentax 70-210 f4 FA and love it. On my last trip the auto focus stopped working, manual focus still works. On the cameras (K-1 M II & K3 M III) screen says MF no matter how I have the AF switch on the lens positioned? Any help would be appreciated!! Thanks.

07-09-2022, 11:45 PM	#3
jazzguy12 New Member Join Date: Apr 2014 Location: santa cruz Posts: 2 Original Poster	Thank you Must be internal, cleaned contacts, & checked to see if it would bounce back (the contact), it did.

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07-09-2022, 03:05 PM	#2
kypfer Pentaxian Join Date: Jan 2018 Location: Jersey C.I. Posts: 3,600	Dirty contacts would be first choice, specifically the one nearest the auto-focus drive (most clockwise, looking at the back of the lens), or just possibly a sticky corresponding contact on the camera. The camera contacts are sprung loaded, it's not impossible for one to get jammed in a depressed position.

07-10-2022, 12:22 AM	#4
Michail_P Site Supporter Join Date: Nov 2019 Location: Kalymnos Photos: Gallery Posts: 3,006	The MF indicator most probably means dirty contacts.

07-10-2022, 02:58 AM	#5
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,253	Check focus limiter position. On mine I sometimes hit the focus limiter unintentionally the lens won't focus unless I move that button back into place.

07-10-2022, 07:53 AM	#6
mlag Loyal Site Supporter Join Date: Jul 2021 Location: Zuiderkempen - Grote Netewoud - Belgium Photos: Gallery \| Albums Posts: 1,413	Originally posted by jazzguy12 ..... the AF switch on the lens positioned? On the lens, ok. But did you check also the AF/MF switch on the body? Maybe re-apply if the switch is slightly out of position...