MarcosP (11.28.19, 11:34 AM): As part of the documentation of the 90D, Canon prepared a brochure of supplemental information addressing the camera's focus behaviour for every lens in Canon's line-up. The brochure is available at http://gdlp01.c-wss.com/gds/8/0300036248/02/eos90d-si2-en.pdf

KeithC (11.04.19, 8:48 PM): Very helpful. I was so frustrated with my Sigma 17-50 2.8 and now its much better.