I was off hiking yesterday with my E-M5 and trusty ZD 12-60 (the 4/3 lens). At one point, I noticed the lens was having an extremely hard time achieving focus, sometimes failing entirely. In those cases, the motor would chatter away for 8-10 seconds before giving up. I tried it again this morning and it now entirely fails to achieve focus, and when it gives up, it makes a whining noise for several seconds. I had the AF motor on this same lens repaired about 18 months ago after it failed entirely. I wasn't thrilled then, but it was a 3.5 year old lens that I'd used quite heavily, so I figured it was just bad luck on my part. This time, the lens hasn't even been used all that much. It could be that I have really bad luck, but I'm beginning to think that the constant adjusting required by the CDAF algorithm has something to do with the AF motor's premature failure. Either way, a $900 lens requiring 2 $300 repairs within 18 months of each other is not making me very happy.