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02-14-2012, 09:14 PM   #1
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Focus problems with the DA 18-135?

I was out shooting with the DA 18-135 on my K-5 today and a weird thing happened - it had a brief period of not being able to focus. I had taken several shots of a tree downed in water, plenty of contrast, and it had focused easily. I moved on away from that, then the light changed so I went back to get some more - and it couldn't focus. Tried focusing on some other things nearby and it was still having trouble. It wasn't completely lost, I was able to focus on a couple of things nearby, but not on the tree or on most things around me. It didn't even seem like it was hunting, just not doing anything. I tried turning the camera off and back on again a few times, that didn't help. When I got home and into a totally different setting, everything was fine.

Has anybody else experienced this? I like this lens and I'm hoping for better luck than I had with DA* zooms. I had SDM failures on both the 16-50 and the 50-125; I was hoping the new focus mechanism of this lens would be an improvement.

02-14-2012, 11:05 PM   #2

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I have been using it for half year or so without any issue. mostly on K-x though.
02-15-2012, 01:40 AM   #3
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Never really had any issues when there was proper lighting. Only had it for around 2 months, but I've been shooting pictures of anything that I see, only time I've experienced focus issues was with very poor lighting(IE: Nearly pitch black).

Did you perhaps get something on the front of your lens/filter? Perhaps very faint fog from change in temperatures could have done it - You'd said the lighting changed, I presume you meant the sun started hitting a different area.

Can't really theorize more without having been there though. Was it just an isolated incident at least?
02-15-2012, 10:29 AM   #4
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I have had this several times with my K200D. I have found that by manually mis-focusing it will then focus. Cannot understand it, but that has been my experience. Perhaps it is too close to the focus point.

02-16-2012, 06:45 AM   #5
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When the light changed, it was really just some of the cloud cover lifting. Slightly brighter. I've had the lens for about seven months and have used it fairly often; this episode was the first time anything seemed amiss. Yeah, I tried changing the focus manually, since that's what worked on my SDM lenses when they were in the early stages of failure, but it didn't make any difference.

It hasn't happened again since that one episode. I'll post again if it does.

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