Product Highlights: EF Mount lens. Range of Aperture: f/2.8-32. Macro focuses at 1:1 reproduction ratio. Floating Lens System of three-group. Ultrasonic Autofocus Motor. Internal focusing system. Override Manual Focus. 1 inch Min. Focus Distance. Optional removable tripod collar. The EF 100mm f/2.8 Macro USM Lens from Canon will focus over the whole range from infinity to true life size (1:1 reproduction ratio) macro. Perfect for details of photographing and small subject material, it serves as a highly sharp prime telephoto lens for portraiture and many other applications. It gives a combination of image quality, brilliant handling and versatility. High-performance ring type Ultrasonic Motor gives silent and fast AF throughout its full time manual focusing and focus range allows the macro shooter or close-up to immediately override AF whenever necessary. A three-group floating system results in brilliant delineation on all focusing distances and a focus range limiter function allows faster autofocus times in one of two accurate ranges. It features a highly developed optical formula with a 3-group floating element system for outstanding close-up performance. Inner focusing means the length of lens remains constant which is specifically important when shooting macro at small distances, especially when you are using an optional ring-type flash. An Ultrasonic motor (USM) provides extra-ordinary AF speed at all focusing distances. Wide manual focusing ring having smooth action and fulltime manual focus override even in AF mode. A focus range limiter allows you set the focusing distance range from 1 inch to infinity or from 1.6inches to infinity. By setting a more appropriate range, focus hunting is reduced and auto focusing time is decreased. Removable tripod collar & Canon ring-type macro flash available optionally.