Canon lenses don’t all focus the same way, and once you start noticing it, it’s hard to unsee. The difference isn’t just speed—it’s character. Some lenses snap into focus with authority, others glide, others feel almost damped, like there’s intention behind every millimeter of movement. Behind the acronyms on the barrel sit seven distinct motor technologies, each engineered around a different idea of what “good autofocus” actually means. Ring-Type USM is where Canon built its reputation.