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07-22-2018, 06:03 AM   #1
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Focus issue with my K3II and Tamron 70-200

Hi Guys,

This is my last desperate try before sending my camera into a service to check and this focus issue annoys me so much I can't tell.

I rencently bought a used K3 II and it's seemed to be working nice. I even did a focus calibration with a test chart I printed out and I was quite relaxed that i'm going to enjoy the sharp images i'll took. Then came the first shock when I used it in real life that it seems when i focus for a far away object it has back focus but for closer objects it seemed ok. I again tried to calibrate the focus to try to find the sweet spot where it sharp at both and again I though it'll be fine.
Then I did some couple shoots and other stuff and again I was shocked how many of my photos again was not in focus. Since then I'm trying to find what's the proper focus adjustment but a lot of times it just feels random if it's sharp or not.
I've read about cleaning AF sensor can help a lot on AF and I did that also with a rocker blower, however I haven't seen any big hair or dirt on the sensor. Hard to see it tohugh I don't have such mirror that dentists are using.
My biggest fear is now that it's operates differently on each focal length and I won't able to calibrate myself properly. I have a Pentax 50mm 1.8 lens besides the Tamron and it's hard to compare the tests with it due to the different focal length but it seems to be ok after calibration.
Long storys short I have a feeling that it does front focusing in general but depends on how i calibrate if that occurs at far or close objects especially at 200mm.

I get best results for far objects if i use no af adjustment, for test chart i would say -8 - 10 working best.

Thanks if advance for usefull advises.

Regards,
Balazs

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07-22-2018, 07:47 AM   #2
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One of the annoying things about zooms is that this can happen. Just to verify all is ok otherwise, does live view give sharp focus at all focal lengths and distances with the zoom?
07-22-2018, 07:59 AM   #3
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Yeah I've forgot that. Live View focusing is spot on with my 50mm but with Tamron 70-200 it's never sharp.
07-22-2018, 09:28 AM   #4
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QuoteOriginally posted by Balazs087 Quote
Yeah I've forgot that. Live View focusing is spot on with my 50mm but with Tamron 70-200 it's never sharp.
Ah ha! In that case no amount of fine focus fixing is going to work. Live View doesn't use the adjustments because they are only needed for PDAF optical focusing. If it won't focus on Live view acceptably it won't focus on optical acceptably. Get a different lens.

EDIT: Normally if you can't get focus on Live View the lens is faulty - however I see that others with more experience with that lens say it is one of the few that fails to work in LiveView reliably and that this is not unique to your copy or camera.


Last edited by UncleVanya; 07-23-2018 at 09:13 AM.
07-22-2018, 10:03 AM   #5
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Tamron 70-200 and AF in Live View in Pentax cameras is not the best possible combination - in fact it does not work at all:/ There were many threads on this topic.
07-22-2018, 02:52 PM   #6
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I don't care really about live view because i never use it, but I wonder if optical focusing has anything to do with it. Anyway thanks for the comments I guess I'm sending in.
07-22-2018, 04:01 PM   #7
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QuoteOriginally posted by pentageek Quote
Tamron 70-200 and AF in Live View in Pentax cameras is not the best possible combination - in fact it does not work at all:/ There were many threads on this topic.
Agreed; I have the same issue with my Tamron 18-250. It's all but useless in Live View with my K3 II; it will eventually focus in, that way, but it's torture to get it. Through the viewfinder, while it's not as fast as even my Pentax 18-55 kit lens, it's still pretty fast and takes very sharp, clear images. It just requires more... patience.
07-23-2018, 07:18 AM   #8
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QuoteOriginally posted by Balazs087 Quote
Hi Guys,

This is my last desperate try before sending my camera into a service to check and this focus issue annoys me so much I can't tell.

I rencently bought a used K3 II and it's seemed to be working nice. I even did a focus calibration with a test chart I printed out and I was quite relaxed that i'm going to enjoy the sharp images i'll took. Then came the first shock when I used it in real life that it seems when i focus for a far away object it has back focus but for closer objects it seemed ok. I again tried to calibrate the focus to try to find the sweet spot where it sharp at both and again I though it'll be fine.
Then I did some couple shoots and other stuff and again I was shocked how many of my photos again was not in focus. Since then I'm trying to find what's the proper focus adjustment but a lot of times it just feels random if it's sharp or not.
I've read about cleaning AF sensor can help a lot on AF and I did that also with a rocker blower, however I haven't seen any big hair or dirt on the sensor. Hard to see it tohugh I don't have such mirror that dentists are using.
My biggest fear is now that it's operates differently on each focal length and I won't able to calibrate myself properly. I have a Pentax 50mm 1.8 lens besides the Tamron and it's hard to compare the tests with it due to the different focal length but it seems to be ok after calibration.
Long storys short I have a feeling that it does front focusing in general but depends on how i calibrate if that occurs at far or close objects especially at 200mm.

I get best results for far objects if i use no af adjustment, for test chart i would say -8 - 10 working best.

Thanks if advance for usefull advises.

Regards,
Balazs
Zooms are a compromise, especially the Tamron SP AF 70-200mm F2.8 Di LD [IF] Macro (A001). You are probably better off fine tuning for the long end of the zoom. If your K-3II focuses correctly with the 50mm f1.8 then its working correctly. The Tamron SP AF 70-200mm F2.8 Di LD [IF] Macro (A001) will not focus correctly in live view at all.

I haven't tried this but you might be able to use a user mode to set your Tamron short zoom focal length fine tune so when you are zooming back in to say 100mm from 200mm you switch to the user mode. I usually only use my Tamron 70-200 at the 200mm focal length as I have several other lens that handle the shorter focal length more easily. Its a good but old design and the fast aperture is quite useful on occasion.

Forget the user mode suggestion I just tried it and that won't work fine tuning is lens dependent only.


Last edited by Larrymc; 07-23-2018 at 07:39 AM. Reason: additional info
07-27-2018, 02:14 PM   #9
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Thanks for the hint though. I'm now pretty sure it needs calibration and it's different on each focal length and focus distance. I'm just hoping the service can fix it. I love the lens.
07-28-2018, 05:30 AM   #10
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QuoteOriginally posted by Balazs087 Quote
I'm just hoping the service can fix it.
I don't think so. As Larrymc wrote, zooms are a compromise, and there is no setting which can fix problems with all focal lengths. Modern lens, for instance Sigma, can be docked into service bay, and have AF fine tuning set for various FLs, but I really do not think Tamron 70-200 has such functionality.
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