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05-08-2009, 01:37 PM   #1
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K20D AF adjustment

I had to use AF adjustment function in K20D to get all my AF lens to focus properly. DA*16-50 and 50-135 and DA 70 Ltd are focusing perfectly now, but the dialed in correction numbers are different for all of them. This seems to be illogical as I thought it was a fault of the camera to cause FF or BF and if the fault is corrected, the correction should be the same for any lens. Am I wrong making this assumption?
Not having a global AF adjustment makes adjustment of MF lenses I have an impossible task as the function does not allow individual adjustment of MF lenses.
I recently acquired two lenses - SMC M 200/F4 and Takumar 135/F2.5. Both are in near new condition but sometimes I have difficulty with focusing and I wonder if this a camera fault or my old myopic eyes. I almost sure these two lenses are just fine.
Any ideas?

05-08-2009, 01:59 PM   #2
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Different adjustments for different lenses are normal. Lenses are not created equal, even from the same product line. This often contributes to people saying that their copy of the lens is "soft" when really it's a BF ing / FF ing lens.

Manual focus don't need autofocus adjustment since there's no alogarithm, just your eyes.

For more accurate manual focusing, you can get a split screen, either the katzeye or a cheapo split screen from ebay. These DSLR screens (any of them) are really quite terrible for manual focusing imho. Sometimes when you replace the screen it has to be corrected for shim thickness (not the screen itself but the metal part that comes with your camera, placed under the screen). My copy from ebay is perfect though. I don't know how this affects the AF adjustment since I don't have a K20D.

If a split screen bothers you you can always use the focus indicator as your manual focusing aid. I usually use both or just the split screen...

Last edited by Andi Lo; 05-09-2009 at 01:46 AM.
05-08-2009, 03:26 PM   #3
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At the peak of my AF lens collection (11 AF lenses at the same time), Not one of the lenses needed "0" they all needed an AF adjustment. They ranged from -4 to plus 7. My 16-50 liked +5, the 50-135 needed +1, and all three of my FA ltds needed something different from one another.

As far as MF goes that improved a lot with the Katz Eye screen. I also tend to use live view for focusing the manual lenses as well, especially the macro lens.
05-08-2009, 10:36 PM   #4
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The K20D does have a global adjustment and 20 lens AF adjustment. However with your older manual lens you will have to apply the global adjustment to *each lens individually* as you use them. A minor inconvenience but what can you do besides using your eyes. I do like using the K20D AF system even with manual lens and its very accurate for me and my old 50mm lens as good as I can do with my eyes, or even live-view, which I like the best really when on a tripod.

05-09-2009, 12:05 AM   #5
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Re: K20D AF adjustment

Thank you guys for answering my question.

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