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04-19-2015, 09:10 AM   #1
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Center AF sensor hunting... rest is better?

Hello. Recently I noticed how the center AF sensor of my K-5 is having more problems focusing than all the other sensors. It may fail in rather easy situations. Any idea what's wrong? It doesn't seem related to the issue that the center spot is too big... Maybe there's dirt on the AF sensor? Or on the mirror?

04-19-2015, 02:12 PM   #2
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Seems odd, usually it is the other way round. Does this happen with different lenses?
04-19-2015, 05:48 PM   #3
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What aperture were you in or is it just in general ? I think the K-3 has a center point of down to F2.8 but I think the aperture is much higher on other cameras. Maybe that is the reason.
04-20-2015, 05:16 AM   #4
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Haven't tested it, but it seems to be the case for both my DA 50 1.8 and my 18-55 AL I.

Something must be wrong with the AF sensor... :-/

04-20-2015, 05:25 AM   #5
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I had read where the AF sensor window can become dusty or dirty and cleaning with rocket blaster or a wet cleaning helped. It is worth a shot. I don't remember where it was, either here or in DPR. You can google it and see but others seem to think it did the job.
04-22-2015, 03:15 PM   #6
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Tried both AF lenses I have, standing in front of a "pretty" 70s wallpaper in dim-ish light. Left most sensor hunted, and hunted, and hunted. Right most hunted, but found focus. All sensors apart from the center one focused pretty fast on the wallpaper. The center one did not. At all. It'd hunt, and hunt, and hunt, or even get stuck at one of the ends, trying to move further in that direction every time I press AF.

I didn't want to touch the sensor window, but I blew into the camera with mirror up (and dust flew my way!), and I cleaned the mirror, which was quite dusty as well. Now it focuses again! Yay!

Thank you very much
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