>I just had a lightbulb moment! I'm not sure if anyone is >familiar with the Tokina 50-135mm f2.8G, nut the manula >focusing sleeve is able to slip forward and back to pop itself >in and out of manual to auto focus as opposed to doing on >camera. A few times not after I've had it in manual, when I >slide the cuff back to auto the camera isn't engaging with the >lens' autofocus screw and spinning. I have to play with the >cuff a few times till the autofocus screw grabs. Now I wonder >if the lens is at fault. I'm going to run the camera with a >few other lens.
I've never had this problem with mine but I can see it possibly being the problem if you don't get the focus ring fully engaged. Also the auto focus on my lens was off when I first got it. It required a -13 AF fine tune. I sent it into Tokina and it came back spot on. BTW my turn around time is very quick. You may not have this problem but you may want to check your lens out for accurate focus.