07-08-2020 11:41 AM
I've the same issue with my Canon 85mm f/1.8. The autofocus is jumping forth and backwards. I've sent to the authorized thechnical assistance. The answer was: we are sorry, but it will cost you $ 210 to rapair it. (a new one lens at B&H Photo costs $ 349).
The auto focus just deteriorate after 3 years, even with a low level of use and no accident, fall or colision. It's a shame. Consider other brands. The Canon 85mm 1.8 is really not reliable.
07-08-2020 12:04 PM
I forgot to report here, but I had exactly the same answer when I took mine to be evaluated. Motor was broken. So I use it as a manual focusing lens.
I still have got nice portraits with the lens, and with 5dmkiii you'll get a confirmation when the focus is set correctly so it is totally usable lens this way too.