Canon EF 100mm f/2.8L Macro IS USM EF100mm F2.8L MACRO IS USM Instruction Manu - Page 6

2. Setting the Focus Mode 3. Switching the Focusing Distance Range To shoot in autofocus (AF) mode, set the focus mode switch to AF. To use only manual focusing (MF), set the focus mode switch to MF, and focus by turning the focusing ring. The focusing ring always works, regardless of the focus mode. After autofocusing in ONE SHOT AF mode, focus manually by pressing the shutter button halfway and turning the focusing ring. (Full-time manual focus) You can switch the focusing distance range to one of three settings: FULL (0.3 m/1.0 ft. to infinity), 0.3 m/1.0 ft. to 0.5 m/1.6 ft., or 0.5 m/1.6 ft. to infinity. By setting the suitable focusing distance range, the actual autofocusing time can be shorter. ENG-5