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Old Sep 20, 2012, 8:37 PM   #1
rle
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Default Sigma 17/50

I have Sigma 17/50, 2.8 on a D7000. The lens continually "hunts" for a focus. The lens tries near & far and continues to not focus on anything long enough to shoot.

Any help??
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Old Sep 21, 2012, 5:03 AM   #2
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Does anything similar occur with any other lenses?
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Old Sep 21, 2012, 7:47 AM   #3
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Hi Tcav,
This is the only lens that acts this way. It is most notable at 50mm and in the <> one meter range. The specs say close focus is 14cm thru out the zoom range.

Thanks,
Rich.
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Old Sep 21, 2012, 8:53 AM   #4
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The specs for the Sigma 17-50mm F2.8 EX DC OS HSM give it a minimum focus distance of 28cm, and a magnification ratio of 1:5.

Is it possible that you're trying to focus on something that doesn't have enough contrast and/or is poorly lit?

If your Nikon dSLR has the 'Live View' feature, have you had better luck using that instead of the eye-level viewfinder?
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Old Sep 23, 2012, 12:00 PM   #5
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Hi TCav, Thanks for your suggestions, but, none of those helped. The lens is under warranty, so I sent it back. Most likely Sigma will say they could not find anything wrong and I'll be out $500.00.

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Old Sep 27, 2012, 5:03 PM   #6
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I was wrong in my assessment of Sigma. They replaced a sensor of some kind in two days, the lens works great, kudos to Sigma.
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Old Sep 27, 2012, 6:43 PM   #7
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That's good to hear.
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