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01-15-2013, 01:21 PM   #1
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Inifinity focus impossible @ 35mm on 35-105mm F3.5 Pentax-A zoom?

Hi all. I recently came into possession of this well regarded Pentax-A zoom, and I have one small question... The lens doesn't seem to be able to reach infinity focus at less than 50mm. Is this normal? What I see is that if I have the lens set to (for example) 1.5m focus, I can turn the zoom dial to 35mm. But if I then proceed to turn the focus dial towards infinity, the lens also simultaneously zooms, reaching about 50mm @ infinity focus. At this point, I can not turn the zoom dial back towards 35mm unless I turn the focus dial back. Is my copy defective or is this behavior normal? Thanks for any insight.

01-15-2013, 03:02 PM   #2
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You have a problem, does the focus ring move in and out of the macro range ?
Turn the focus ring to the left until it stops then you should be able to push it forward and then be able to rotate it into the green macro position.
I have one of those and the focus and zoom are completely independent.
01-15-2013, 03:44 PM   #3
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Thanks bobpur. I have found the problem, and it was both simple and embarrassing, though thankfully quite fixable. The lens has a generic front cover with an elastic band tying it to the lens to avoid losing it. As it happens, the elastic was over the part of the barrel that need to retract itself into the rest of the lens in order to reach infinity focus at 35mm. Thus the lens was physically impeded in its movement by the width of the elastic band, producing what I described in my first post above... As Homer Simpson would say: "Doh!" (I guess it's preferable to be a little embarrassed rather than having a broken lens!) After moving the elastic out of the way, everything's now working fine. And yes, macro mode engages properly. Thanks for your feedback!

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