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07-14-2011, 08:23 AM   #1
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Join Date: Sep 2010
Location: Connecticut
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18-135mm problem: "stuck" aperture?

I'm about to go through Pentax service to see what they can do, but I thought I should throw the question out to this community.

I was using my 18-135 on a K5, taking pictures just fine, jumping between modes (of which aperture priority was one). All of a sudden, the viewfinder is VERY dark and grainy, and the focus is VERY slow (if it will focus lock at all). It almost seems like the lens may be locked in its smallest aperture, even though the camera will let me change what it thinks the aperture value is.

This of course happened while I was on vacation. I switched to the 55-300 that I had also brought along, and everything was fine. Back to the 18-135 and no luck. (I was forced to use my panasonic "FZ" for the remainder for "normal" focal length shots --although at least I did pack that as a small backup...)

When I got home, I tried the 18-135 on my older Kx, and I have the same problem. So it definitely seems like a problem with the lens... I've had the lens for about 6 months, and no problems before now...

Any thoughts on what the problem might be or things to try to fix it before sending it in for service?


07-14-2011, 11:27 AM   #2
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Join Date: May 2010
Posts: 167
There is a small lever on the back of the lens that controls aperture. Check that it's operating freely.
07-14-2011, 12:53 PM   #3
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Join Date: Feb 2011
Location: Philly
Posts: 395
It seems like my 18-135mm has been focusing reeeeeaaaaalllly slow lately as well. I think it's a lot worse in lower light. It seems to focus normally in good light, though.
07-14-2011, 02:04 PM   #4
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Join Date: Aug 2008
Location: Michigan, USA
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Sounds like the aperture lever has let loose of the actual aperture blades and they are staying closed. The lens is probably under warranty so I would send it for repair.


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