DISASTER-Please Help!!

Darren Troy C

Sigma 70-200mm 2.8 II DG HSM Macro.

WILL NOT AUTOFOCUS!!! Worked just fine up until 7am this morning. There is a very, very faint "clicking" when the shutter is depressed, but nothing else! :boid :bash :cry

HSM gone? Why won't the camera move the lens? :scratch

AAARRRGGGHHHHHHHH!

Pass me a gun, please.

Darren Troy C

D300.....and oddly enough....it's working now! WEIRD. It did sit in my truck all night and temps got into the low 20's. Could this in any way effect what I have explained here?......anyone? Never heard of it myself but ya never know...

ziggy53

How cold was the lens when you first tested it and did you mount it on the camera or was it already mounted?

Darren Troy C

Not on camera yet....mounted directly as was ...COLD!! I'm guessing not much warmer than the outside temp....which was around 26 this morning. You'd think if temp had anything to do with it, warmer environment would have remedied that. I think it's what was previousl mentioned....the "screw drive"....? I have noticed that when mounted this lens has EVER SO SLIGHT (and I mean that in a microscopic kind of way) play in it. Real bummer of a side effect for a brand new lens b/c the glass itself is phenomenal and the thing is quick too!

ziggy53

Idlewild wrote:

Not on camera yet....mounted directly as was ...COLD!! I'm guessing not much warmer than the outside temp....which was around 26 this morning. You'd think if temp had anything to do with it, warmer environment would have remedied that. I think it's what was previousl mentioned....the "screw drive"....? I have noticed that when mounted this lens has EVER SO SLIGHT (and I mean that in a microscopic kind of way) play in it. Real bummer of a side effect for a brand new lens b/c the glass itself is phenomenal and the thing is quick too!

Sigma HSM are like Nikon AF-S in that the motor is electronically controlled and in the lens body. It doesn't sound like it was that cold that it should have been a concern, but it is worthy of consideration as a possibility.

Does that lens have an AF switch (in addition to the AF override)?

Robinivich

Electronic failure of a lens that mysteriously repairs itself with time, really cold temperatures are involved? (I think it's safe to assume you're talking fahrenheit:D)

Sounds like condensation on electrical contacts causing a short that led the camera to think it shouldn't use the AF motor, or the electrical impulses that control it didn't make it through. Once the condensation was gone, problem went away.

Avoid sharp changes in temperature and you'll probably never experience it again.

Darren Troy C

ziggy53 wrote:

Sigma HSM are like Nikon AF-S in that the motor is electronically controlled and in the lens body. It doesn't sound like it was that cold that it should have been a concern, but it is worthy of consideration as a possibility.

Does that lens have an AF switch (in addition to the AF override)?

No AF switch, Ziggy. I like the "condensation" angle, Robinivich. Makes me feel much better regarding the issue @ hand...makes perfect sense.

Thanks guys.

Robinivich

Idlewild wrote:

No AF switch, Ziggy. I like the "condensation" angle, Robinivich. Makes me feel much better regarding the issue @ hand...makes perfect sense.

Thanks guys.

Glad to be of comfort! Obviously keep aware, and if you experience something like that again, but unrelated to moisture, I'd try a pencil eraser gently rubbed on the electrical contacts, in case they're corroded. Something tells me you won't have to though