Steve'sDigicams

rle · Sep 20, 2012, 8:37 PM

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??

TCav · Sep 21, 2012, 5:03 AM

Does anything similar occur with any other lenses?

rle · Sep 21, 2012, 7:47 AM

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.

TCav · Sep 21, 2012, 8:53 AM

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?

rle · Sep 23, 2012, 12:00 PM

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.

r.

rle · Sep 27, 2012, 5:03 PM

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.

TCav · Sep 27, 2012, 6:43 PM

That's good to hear.

Sep 20, 2012, 8:37 PM	#1
rle Member Join Date: Oct 2011 Location: Manheim, Pa Posts: 72	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??

Sep 21, 2012, 5:03 AM	#2
TCav Senior Member Join Date: Sep 2005 Location: Washington, DC, Metro Area, Maryland Posts: 13,755	Does anything similar occur with any other lenses? __________________ The lens is the thing. 'Full Frame' is the new 'Medium Format'. "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.

Sep 21, 2012, 8:53 AM	#4
TCav Senior Member Join Date: Sep 2005 Location: Washington, DC, Metro Area, Maryland Posts: 13,755	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? __________________ The lens is the thing. 'Full Frame' is the new 'Medium Format'. "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.

Sep 27, 2012, 6:43 PM	#7
TCav Senior Member Join Date: Sep 2005 Location: Washington, DC, Metro Area, Maryland Posts: 13,755	That's good to hear. __________________ The lens is the thing. 'Full Frame' is the new 'Medium Format'. "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.

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Sep 21, 2012, 7:47 AM	#3
rle Member Join Date: Oct 2011 Location: Manheim, Pa Posts: 72	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.

Sep 23, 2012, 12:00 PM	#5
rle Member Join Date: Oct 2011 Location: Manheim, Pa Posts: 72	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. r.

Sep 27, 2012, 5:03 PM	#6
rle Member Join Date: Oct 2011 Location: Manheim, Pa Posts: 72	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.