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07-14-2020, 10:37 PM   #1
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Weird Live View AutoFocus behavior

Hello fellow pentaxians

I have some weird behavior from my K-5

Live view is working perfectly in terms of AF accuracy with my tamron 17-50, 18-55 kit lens and tamron 70-300

I just bought a used Pentax 16-50 2.8 which is working perfectly in terms of AF accuracy with PDAF (zero AF microadjustment). It is also spot on in both PDAF and CDAF while used with my K-50

When I use it with live view in my k-5 it simple refuses to focus correctly in anything farther than a few meters. It hunts and it locks AF in some completely wrong place.
Any ideas (including tests on developers menu)? both lens(on K-50) and camera(with all other lenses) are working, it is just the combination that is not working...

PS: battery is fully charged

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07-14-2020, 11:32 PM   #2
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Bit of a long shot, but always worth asking ... is the camera firmware up to date? currently at v.1.16 Latest K-5 Firmware Update : Software Downloads | RICOH IMAGING
07-15-2020, 12:41 AM   #3
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QuoteOriginally posted by kypfer Quote
Bit of a long shot, but always worth asking ... is the camera firmware up to date? currently at v.1.16 Latest K-5 Firmware Update : Software Downloads | RICOH IMAGING
Yes it is: (
07-15-2020, 01:11 AM   #4
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Clean SDM contacts on your K5
Could be the beginning of SDM failure of the DA*16-50. It is a known problem

07-15-2020, 01:24 AM   #5
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QuoteOriginally posted by photogem Quote
Clean SDM contacts on your K5
Could be the beginning of SDM failure of the DA*16-50. It is a known problem
Sdm is working just fine in both PDAF and CDAF in my K50 and in the sellers K3. Also perfect in my K5 when using focus through viewfinder. I don't think that's the case...
07-15-2020, 02:45 AM   #6
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Older DSLR have had more problem with CDAF LV focus, than newer cameras.
Especially on lenses with built in AF-motors.

Does it make any difference if using CDAF or PDAF in LV on K5? With PDAF it stops LV and switch over to OVF during AF and the return to LV.
07-15-2020, 03:02 AM   #7
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QuoteOriginally posted by Fogel70 Quote
Older DSLR have had more problem with CDAF LV focus, than newer cameras.
Especially on lenses with built in AF-motors.

Does it make any difference if using CDAF or PDAF in LV on K5? With PDAF it stops LV and switch over to OVF during AF and the return to LV.
Yes it's working with PDAF during live view, but is not a convenient way to focus...
07-15-2020, 07:41 AM   #8
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Same subject? The "C" in CDAF stands for contrast and in the absence of adequate contrast and detail, it simply fails or becomes less accurate.


Steve

07-15-2020, 08:12 AM   #9
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QuoteOriginally posted by stevebrot Quote
Same subject? The "C" in CDAF stands for contrast and in the absence of adequate contrast and detail, it simply fails or becomes less accurate.


Steve
It can't focus on a car's plate at 10 meters under sunlight...
07-15-2020, 01:49 PM   #10
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K-7 user here, using LV with the camera on a tripod. I have had mixed results with auto focus in LV, so usually focus manually with the screen zoomed in to x8 or x10 magnification. I'm not in a hurry shooting this way, so the extra time involved helps get the very best from whichever lens is on the front. If letting the camera focus, I use CDAF in LV.
07-15-2020, 01:56 PM   #11
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Thank you all for your replies but with the Tamron 17-50 which is a really similar lens I have no problems at all. CDAF is really fast and accurate! It seems I'm the only one facing this problem, so I will shoot you a video to show you the problem
07-23-2020, 10:14 AM   #12
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Below the problem in video. Note that both lenses AF is spot on while using PDAF.
AF is impossible with 16-50 and CDAF even in more contrasty scenes, this is just an easy target, as I hadn't a tripod with me.


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