See It Read Our Canon RF 24-240mm F4-6.3 IS USM Review (Jim Fisher) The other zooms, the low-cost RF 24-105mm F4-7.1 and RF 24-240mm F4-6.3 , are geared more toward beginners and photographers who The RF 24-240mm F4-6.3 IS USM uses Canon's NANO USM system which combines conventional ring USM AF, and features a diminutive chip-shaped ultrasonic motor that's engineered to help deliver high-speed, smooth, precise and near-silent operation, plus full time manual focus (when using One-shot AF). cnKa.