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10-20-2020, 08:00 AM   #1
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New onset front focus

I have K1mk2 that i purchased over a year ago from KEH, and have had no problems until noticing this week that i missed shot after shot. They were all front focused by multiple feet in some cases. My camera has never been damaged in any way so I thought it was just the lens (Sigma 85 f1.4) until I tested all of them and found each needed significant AF tuning. I still cant achieve critical focus with the Sigma unless the subject is close. I've attached a chart of my lenses and their AF Tuning settings. Is this fixable? If so, does anyone have experience with this problem, and what could have caused it? I mainly shoot real estate so it's not killing me, but I have some event work coming up and shooting MF is not a skill I've mastered.

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10-20-2020, 09:27 AM - 2 Likes   #2
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Probably a long shot but check the mount screws and make sure they are tight. A loose mount will cause this.

Otherwise I suspect the camera got bumped at some point, likely not even anything you noticed. It can be sent to Precision for re-calibration.
10-20-2020, 09:30 AM - 2 Likes   #3
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QuoteOriginally posted by jbb356 Quote
Is this fixable?
It may be due to dirt or haze on the PDAF detector. As for achieving consistent critical focus with an 85/1.4 using PDAF, I wish you the best of luck.


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10-20-2020, 01:20 PM   #4
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Use a rocket blower on the AF sensor

10-20-2020, 01:23 PM   #5
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QuoteOriginally posted by stevebrot Quote
It may be due to dirt or haze on the PDAF detector. As for achieving consistent critical focus with an 85/1.4 using PDAF, I wish you the best of luck.


Steve
Thanks for the suggestions guys, but the mount is tight, and the PDAF was all clean. The Sigma at 1.4 was tricky for sure, but I never had full body shots missing focus by a 6-12 inches. Using a focusing chart, I was able to get consistent focus starting at f1.8. I'm having trouble using manual focus since I'm right eye dominant, but I cant find a good diopter setting that matches when the camera alerts to in focus, and what my eye says is in focus. The camera consistently alerts focus and the resulting image is still front focused by a significant margin. Guess I'll be contacting Precision!
10-20-2020, 01:28 PM   #6
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You should also compare the results between PDAF and Liveview if you have not. See if you can get consistent results in Liveview and then compare that to what you see in the viewfinder.
10-20-2020, 01:46 PM   #7
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QuoteOriginally posted by jatrax Quote
You should also compare the results between PDAF and Liveview if you have not. See if you can get consistent results in live view and then compare that to what you see in the viewfinder.
Just tried this and attached the results. Live view was dead on. I had the same results as PDAF when I focused manually to where the camera alerted to proper focus. I was able to get a happy setting on the diopter using this test though.
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10-21-2020, 02:02 AM - 1 Like   #8
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This clearly shows a misalignment between the the af module and the sensor distance. I had this on my k-5 which was dropped on its bottom by its previous owner, so much so that the bottom plate was bent. upon releasing and rescrewing it back on place the problem was gone, probably because there was some tension release between the parts.
The K-7/K-5 have a underneath the bottom plate which calibrates the af module distance(search forum for thread), I guess the K-1 might have it too.

10-21-2020, 04:02 AM   #9
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QuoteOriginally posted by jbb356 Quote
Just tried this and attached the results. Live view was dead on. I had the same results as PDAF when I focused manually to where the camera alerted to proper focus
Your PDAF is out of alignment. You can correct this in the AF/FA menu....Autofocus Fine Adjustment.
10-21-2020, 05:26 AM   #10
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QuoteOriginally posted by shyrsio Quote
This clearly shows a misalignment between the the af module and the sensor distance. I had this on my k-5 which was dropped on its bottom by its previous owner, so much so that the bottom plate was bent. upon releasing and rescrewing it back on place the problem was gone, probably because there was some tension release between the parts.
The K-7/K-5 have a underneath the bottom plate which calibrates the af module distance(search forum for thread), I guess the K-1 might have it too.
How strange, it's been sitting on my desk since last use but I'll check that out, thanks!

QuoteOriginally posted by pschlute Quote
Your PDAF is out of alignment. You can correct this in the AF/FA menu....Autofocus Fine Adjustment.
Right, I did that and now most of my lenses are at -10 after having already performing fine adjustment previously. My focus window has shifted forward, and should be 5 to -15 instead of 10 to -10.
10-21-2020, 06:45 AM   #11
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QuoteOriginally posted by jbb356 Quote
Right, I did that and now most of my lenses are at -10 after having already performing fine adjustment previously. My focus window has shifted forward, and should be 5 to -15 instead of 10 to -10.
This is the first time I have heard of the PDAF alignment moving over time. My K1 is 4 years old and the AF/FA is as correct now as it was when I originally calibrated it. You can send it in to get it re-centred.
10-21-2020, 07:02 AM - 1 Like   #12
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QuoteOriginally posted by pschlute Quote
This is the first time I have heard of the PDAF alignment moving over time. My K1 is 4 years old and the AF/FA is as correct now as it was when I originally calibrated it. You can send it in to get it re-centred.
I was able to enter DEBUG MODE and adjust the focus by -80μm and am getting consistent focus with the Sigma 85 @ 1.4. I'll go through the other lenses and make adjustments as necessary. I don't know how any future firmware updates will effect my current settings, but I'll cross that bridge when I get to it. I'm looking at picking up a second body soon, and when I get some down time I'll send it in for assessment.
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