Electronic focusing
Manual doesn’t always mean mechanical
he majority of Canon’s EF and EF-S T ‘USM’ (Ultrasonic Motor) lenses for EOS DSLRs have a physical connection between the focusing ring and the focusing optics. There are exceptions though, such as the EF 85mm f/1.2L II USM and the EF-S 18-135mm f/3.5-5.6 IS USM, both of which utilize electronic manual focusing instead. Electronic focusing is a focus-by-wire system, where the camera adjusts the focusing distance via a motor when you turn the focusing ring. Lenses that are designed for the mirrorless EOS R System, as well as DSLR lenses that are equipped with an ‘STM’ (Stepping Motor) instead of a USM, also only offer electronic focusing.