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10-29-2014, 12:11 AM   #16
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QuoteOriginally posted by candgpics Quote
Hi:
So, I guess my questions are:

1. Has anyone else had what appears to be erratic autofocus and micro adjustments issues on their K3 such that you can get different results under testing out the various micro adjustments on different days and under different lighting conditions?
Yes, I had problems with my K-3 and sent it in for repair. Pentax replaced the AF module and did som adjustments and it is working as it should now with no problems at all.

10-29-2014, 06:01 AM   #17
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QuoteOriginally posted by asharpe Quote
I usually use manual lenses, but I was quite curious about my K-3's autofocus. It *seemed* ok to me with my Pentax-F 35-70, Pentax-F 50/1.7, Takumar-F 70-200 and the 18-55 kit lens. though. So I tried this test image from Northlight-images, manually focusing the lenses from 50 x focal length with magnified live view, then switching off live view, switching to AF, and pressing the AF button. None of the lenses moved when AF focusing after the manual focus and the image was the same, indicating that they did not need any adjustment. A little disappointing, because I was looking forward to using that feature of the K-3. But, I didn't need it.
I've been under the impression the better way to test this is to de-focus before you activate the AF. That way you force the camera to focus and can see how well it does.
10-29-2014, 08:54 AM   #18
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QuoteOriginally posted by IchabodCrane Quote
I've been under the impression the better way to test this is to de-focus before you activate the AF. That way you force the camera to focus and can see how well it does.
Right, that's my approach too. Intentionally defocus and use the PDAF to focus on the target. Then switch to manual focus, engage magnified live view, and see if there's any improvement to be had, making a note of which direction the focus ring needs to be turned.

Make adjustment and repeat ad nauseam.
10-29-2014, 09:32 AM   #19
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QuoteOriginally posted by IchabodCrane Quote
I've been under the impression the better way to test this is to de-focus before you activate the AF. That way you force the camera to focus and can see how well it does.
Well, that wasn't what the Northlight-images site recommended, but if your approach works well for you, that's good.

10-29-2014, 11:20 AM   #20
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I think I would do it this way:

1) Switch to MF. Use Live View and focus peaking to focus on a subject (CDAF)

2) Switch to AF and use PDAF to focus. If the lens moves at all, then there is possibly a need to dial in some compensation.
02-15-2015, 10:56 AM   #21
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NEW moirč-based AF ADJUST method!

With SDM lens you may not notice nor hear lens focusing movement
There is an interesting method:
www.dpreview.com/forums/thread/2996948

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QuoteOriginally posted by jbinpg Quote
1) Switch to MF. Use Live View and focus peaking to focus on a subject (CDAF)
2) Switch to AF and use PDAF to focus. If the lens moves at all, then there is possibly a need to dial in some compensation.
02-15-2015, 11:42 AM   #22
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My k-3 had the same behavior you describe. Drove me crazy, none of my lenses would focus consistantly. I sent it back to Pentax to fix under warranty but they simply returned it and told me it was "within spec". This is why I'm shooting with a K-5 now, hope you have better luck than me.
02-15-2015, 01:37 PM   #23
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I finally bit the bullet and sent my K-3 in for the "mirror flapping" issue. Got it back in less than 1 week. Kudos to Precision. They also adjusted the AF module and now "magically" all my lenses AF with no need for micro adjustment.

YMMV

Michael

02-15-2015, 02:01 PM   #24
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Do EXIFs hold AF micro-adjustment values?

Are AF micro-adjustments values written to Exif files?
I cannot find this data in Exifs...

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QuoteOriginally posted by MJSfoto1956 Quote
They also adjusted the AF module and now "magically" all my lenses AF with no need for micro adjustment.
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