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03-03-2011, 05:44 PM   #1
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Join Date: Nov 2008
Location: Park City, Utah
Posts: 208
Anyone using the af adjustment oh there 645d

I have been playing around with my fa lenses and using lens align trying to dial in front focus back focus issues with fa lenses
Overall my results have been all over the place, dependent on camera to subject distance and so on
Michale Tapes has recommended distances to use from his ruller on lens align to camera based on focal length and speed of lens, but his calculator is based on FF 35mm
Not sure that really matters.
I did a test the other day where i used my fa 120mm lens which according to the lens align test showed it needed no af adjustment, well at short distance images were in focus but at infinity the lens was back focusing.

So.. I was just curious if anyone else is using the the af adjustment and there experience


03-03-2011, 05:55 PM   #2
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Join Date: Dec 2010
Photos: Gallery
Posts: 164
I use it for both my canon and 645d. One thing I have learned is to take three readings and purposes unfocused after each test. All cameras af systems have a tolerance on focusing so it supposedly will never be 100% accurate...according to canon.
03-05-2011, 05:03 PM   #3
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Join Date: Apr 2010
Location: Alberta
Photos: Gallery
Posts: 36
I have gone through the trouble of using the LensAlign system to figure out exactly where all my 67 lenses focus (i.e. ahead, behind, right on) and then I manually adjust the value for the various lenses when I mount them . This is using the focus assist, of course, since all the 67 lenses are manual focus anyway. I have already suggested to Pentax that they allow for multiple manual lens values to be saved and recalled in the next firmware update.

Now, does this actually help in the field? I am going to try Lloyd Chambers suggestion of using a loupe and check it out.

03-06-2011, 10:59 AM   #4
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Join Date: Jan 2011
Location: varese
Posts: 27
in my case, only 120 macro and 300/4 required AF calibration.
The 120 was frontfocusing, and required a consistent -10. Now it focuses perfectly at all distances.
For the 300 only -3 was required, and is now spot on at all distances.
All other lenses, 35,75, 150 and 45-85 didn't require calibration.


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