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11-26-2010, 03:00 PM   #1
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Issue with Sigma 18-250mm OS HSM

I just got this lens from BH Photo a few days ago, and I've noticed that its very slow at focusing compared to my other two non HSM lenses a Pentax 18-55 and a Tamron 28-105. Its about 2x slower going from one end of the focus range to the other, and along the way produces a high pitched whine. I'm wondering what other people experienced with this lens.

I'm thinking I have a bum lens and may exchange it for another one.




Here's a YouTube Video



Last edited by varian; 11-26-2010 at 03:33 PM. Reason: Added video
11-26-2010, 03:47 PM   #2
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You report is possibly the first negative comment that I read on the Sigma 18-250mm OS HSM.

First let me ask you: do you use the lens OS? In the affirmative, did you switch off the camera IS ?

The lens OS is redundant with the camera IS. You choose one or the other, but not both.

Second, if you switch off the camera IS, test the lens with OS on and OS off. If you still have some problem with slow focus, send back the lens for exchange.

Hope that the comment is helpful.

PS: I have the DA18-250mm but I was very seriously considering the Sigma 18-250m OS HSM, although it was not yet available with K-mount in Oz at the time.
11-26-2010, 04:24 PM   #3
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I have the Sigma 18-250, and I see and hear nothing unusual about the end to end focus hunting in that video (I don't hear any high pitched whine). It looks to be perfectly fine.

That jerky AF (with the cap off) is a bit odd, though I can't say anything without knowing what it's trying to focus on, and how close it is.
11-27-2010, 07:02 AM   #4
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When I uploaded the video to YouTube the high pitch sound is gone! It must be the way the sound is compressed.

I've tried it with the OS on and off on both the camera and lens. I thought the benefit of the HSM is a faster quieter focus.

12-12-2010, 03:51 PM   #5
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Hi! I just received my brand new sigma 17-70 HSM, and have the exact same problem! I confirm, it makes sometimes a strange and high pitch noise wich is for sure not normal. The thing, is that mine works well sometimes, everything goes well, and suddenly, all the problems appear again. It won't find the focus, except after a very long try, over 10 sec most of times... And also, when it is on "infinite", if i try to focus on something close, it just wont turn all the way in once, but saccade many times to get there.

I'll make a video tomorrow, and return it to get an other one.
12-12-2010, 06:26 PM   #6
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That lens does not have focus shift. Why are you moving the focus ring with the lens switch in AF, not MF??? Your not suppose to do that, read your directions. You may have damaged the lens.
12-13-2010, 10:42 AM   #7
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I noticed that also, but, I didn't do it on mine, and still, it has the same problem. So I wouldn't bet this is the problem
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