Sigma 17-50 Auto Focus Issue

I purchased a brand new Sigma 17-50 a couple weeks ago. I was very very happy with it. Very fast focus, no back or front focus issues, etc. This morning I go out to the beach to take pictures and it would not lock on to focus, and when it did beep like it locked on focus, it was way out of focus. Lighting was good and I was using the center focus point. Can anyone think of anything to check before I send this back. AF was clicked selected on the lens as well and it was on one shot auto focus. Any help would be great!

Did you MFA another lens and select the adjust all by same amount option instead of just that one lens?

Hmm, yea if you micro adjusted another lens and that setting was applied to all lenses then that could be your problem.

What was your subject? Moving, static?

One shot or AI servo?

No, I have a 60D, so no MFA. I searched on the internet and found someone with a 7D that had the same exact issues. I just put the lens on a 50D that my dad has and the lens did the same thing...hunt, hunt, hunt, hunt, hunt. And the very few times that it did lock focus it really was not in focus at all, not even close. I am really not happy about having to send the lens back on my dime all the way to New York and then not have a lens in that focal range to shoot with.

Static object, good lighting, one shot auto focus. I even switched to back button focus to see if that would change anything, and it still did the same thing. This went from being a tack sharp, ultra fast focus lens, to a paper weight in 1 day. Yesterday it was absolutely perfect.

What were you focusing on? Sky, water, beach?

Does it still do it in other conditions? What about just around the house..

When I first took it out of the bag, I focused on a person. It would not focus, then I tried to focus on anything that was around, a log, rock, etc. nothing worked. Then I took it home and tried to focus on things around the house. Keys on the table, etc, nothing would focus. It would hunt 99% of the time and then every once in a while it would beep like it locked focus but the image through the view finder and the actual picture taken was very very OOF.

Try: turn off your 60d, turn off OS of your lens, take off lens from your cam, wait a minute then put it back together. Try switching Af/mf switch. Hope everything will be ok. Mine works perfectly since day 1.

As a sanity check, use another lens with AF, and focus, to rule out any issues with the Camera. I've have my sigma for about a year without any problems. If other lenses work but not the Sigma, you may have a AF motor issue. Send it back, that's what warranties are for. Good luck.

As above if another lens does work just return the Sigma to where you purchased it.

I had my sigma for months my lens never hunts its spot on every time try resetting your camera to default settings try using manual focus take a pic like that then switch it back to auto....

You didn't have the camera accidentally bumped to A-DEP mode by any chance ? Happened to me once.

Thank you all for your help. I did reset all my setting on the camera body and it is not on A-DEP mode. I tried focusing with my dads 70-200 F4 IS and it was fast as usual, no issues there. I will try what raptor suggested and if that does not work it will go back. Does anyone know if there are overseas version of this lens and US versions. I purchased from 47th Street Photo and they said they are an authorized dealer. The warranty card in the box is not in English.

Try taking it back to the store for a replacement there first, they may just swap it out!

Allan.L wrote in post #14308705
Try taking it back to the store for a replacement there first, they may just swap it out!

I purchased it on EBAY from 47th Street Photo. I have contacted them and asked for them to swap it out. If not I will just send it to Sigma as a warranty. I purchased it brand new and they say they are an authorized dealer. I just don't like the fact that I will be without for at least a little while. Thanks to everyone again for their suggestions.