I'm not sure why that is the case with the 85GM, the 135GM is absolutely silent by comparison. I had the Canon 85 1.2 II when I was with Canon and I don't recall that lens being as loud and it it was it wasn't the "grinding" type sound I hear with the GM.
when outdoor it's not much of a big deal but when its indoor and quiet its loud. but yes the quality and image from it is what matters the most. I was just shock to hear how loud it really was when its quiet :P will not be returning it for that matter. It's a keeper.










