The lens offers such features as a three-group floating system for exceptional close-up performance; a secondary diaphragm that blocks stray light at f/2.8, which increases contrast when shooting wide open; a ultra-sonic monitor (USM) that provides outstanding autofocusing speed at all focusing distances; a wide manual focusing ring with smooth action; and full-time manual focus even in AF mode. The first lens in its class to feature inner focusing, the lens carries a one-year warranty.  Bring small things into full-sized view with the Canon EF 100mm macro USM lens. Macro lenses can uncover detail that would be impossible to detect by the eye and give new perspective to extremely minute subjects such as insects or the petals of a small flower, and this lens is no exception.

 

• Diagonal angle of view: 24 degrees
• Focal length: 100mm
• Maximum aperture: 1:2.8
• Lens construction: 12 elements in 8 groups
• Focus adjustment: Inner focusing system with USM
• Closest focusing distance: 1 foot (film plane to subject)
• Filter size: 58mm
• Dimensions: 3.1 inches in diameter, 4.7 inches long
• Weight: 21.1 ounces

This telephoto macro lens is capable of focusing to life-size (1X) without attachments. Although it replaces the EF 100mm f/2.8 macro lens, it is a completely new design. It incorporates a ring-type USM giving quiet, high-speed autofocus. The full-time mechanical manual focus gives very smooth manual focusing. Also, during focusing the front ring does not rotate making use of front-mounting accessories like macro ring lites simple and effective. "Three-group floating" focusing construction uses three independently moving groups, which holds focusing-related changes of aberrations to a minimum giving excellent image quality all the way from infinity to life size. For the first time in a 1X focusing telephoto macro lens, inner focusing is used.The lens length remains constant and a long working distance of 149mm makes worrying about getting too close to the subject unnecessary.