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08-02-2010, 07:38 PM   #1
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F 70-210mm Focus Issue

I just recently acquired a used F70-210 for my K7. It seems to work well in most configurations but I'm having difficulty focusing at infinity when zoomed to 210. It seems as though it needs just a litle more on the focus ring and it would be ok but of course, it's at the maximum and sill not in focus. I know the previous owner and he used it on his 35mm with no issues. Has anyone else experienced anything like this or is there a problem with the lens?

08-03-2010, 12:43 AM   #2
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This definitely sounds like a lens problem. Do you know if it's the camera that thinks the image is out of focus and just tries to nudge the focusing right further to the right, or is the image actually out of focus? If it's the former, then you'll be able to calibrate the AF system to compensate for the flaw.

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08-03-2010, 06:15 PM   #3
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Good question. I'm going to try the lens on a K10 and a 35mm SF-1 tomorrow and will be able to confirm where the problem lies. If the same on those, then the lens is probably toast.
08-04-2010, 06:40 PM   #4
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Checked on the K10 and SF-1. Seemed to work at first on the K10 but then couldn't lock on at infinity. Same for the SF-1. I tried adjusting focus on my K-7 but even at both extremes (-10, +10), it didn't make any difference so it would appear that the problem lies with the lens. Good that itisn't a camera problem but now I have to look for another lens.


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