I recently (about 2 months ago) purchased a Canon 85mm f/1.8 through B&H and have been planning to use it in an upcoming wedding shoot at the end of August. Lately I've been noticing significant issues with missed focus, particularly front focus. Obviously the problem is most pronounced wide open, but it's even missing focus at f/2.8, especially with distant subjects. At first I attributed the issue to my technique, but I've since tested the lens extensively on static subjects and it does seem to be consistently front-focusing. The focus issue only manifests with phase-detect AF, images taken with live-view contrast-detect AF are spot-on.
Has anyone had experience with sending a poorly focusing lens in to Canon? Did they repair it, and if so, how long did it take? I assume I wouldn't get it back in time for the event in 5 weeks if I sent it in tomorrow.
Both of the photos below were shot at f/2, the top one in live view and the bottom through the viewfinder, AF mode was one shot
Live view AF
IMAGE LINK: https://flic.kr/p/opQY5Q 85mm f/1.8 phase AF by jt354, on Flickr