Sigma 24-70 EX DG Macro stops focusing

[gunthermoose]

My Sigma 24-70 EX DG Macro takes super sharp pics but sometimes refuses to autofocus... any ideas...

[4x4rock]

Does it stop responding when you 1/2 press the shutter? Nothing at all?

Did you check the contacts? and make sure that you're not too close to the subject which maybe out of the lens focus area.

If it can be reproduce consistently, I'd say contact Sigma and send it in.

[gunthermoose]

Will check those things next time it happens..

I've only noticed it after the camera has been on for a time.. so maybe it is the contacts.. It happens very rarely but annoying when it does.
If I turn off the camera and remove & replace the lens it seems to right itself...

[LightRules]

Interesting. In all my years with the lens it never acted that way. Definitely clean the contacts and if it persists, give Sigma a holler.

[8lias]

You are not alone, I experience that same thing. I contacted Sigma before and they recommended cleaning the contact and I did, didn't help much though. Another thread recommended leaving it on with the 1 minute sleep mode. However, I am still experience once in a while, what I do is giving it a little twist as if I am changing the lense, therefore reactivating the contact between the lense and the camera body. Don't know why it does that but this lense is too nice so I don't get bother by it.