Sigma 70-300mm 1:4-5.6 lens problem when focusing

[Adam R4]

Hey every one, ive got a Sigma 70-300mm DG macro lens and im having some troubles with focusing.

What is happening is when im manually focusing the lens does'nt come out smoothy, almost like its catching on its outer body and feels notchy. This happens on and off the camera body.

And also when im using auto focus it physically does'nt work, the small wheel in the body seems to be spinning round and jumping in and out of where it should be on the lens. The lens is attatched propperly.

I bought it about 10 months ago, but i cant remember where i put the warranty papers as there not in the box. :|

Im going to take it to my local photography shop next week and see what they say but meanwhile can anyone offer any assistance or atleast tell me what the problem may be please?

Cheers, Adam.

 

[Bendihossan]

Sounds like a damaged AF motor to me

 

[Adam R4]

Its the actual lens itself. I need to mension that actually!

It does the notchy manual focus bit on and off the camera body.

 

[lepster74]

Sounds like the gears in the lens itself have come loose and/or broken.

Is the macro switch on the lens fully on or off, since when it's on it limits the zoom range between 200mm - 300mm. If this was slightly on it might have caught and something broke inside.

 

[Adam R4]

The macro switch is fully off.

What i don't understand is that it was fine around sunday morning (last week) and i placed it on the dining room table for about three quarters of an hour, i came back to it and it seemed slightly rough when i used it to focus on my car, it then got worse. But i know that no one went in there as there was no one else in the house.

So yeah, maybe the gearing in the lens is broken from a previous slight nock of some kind.

Adam.