This is a Lens EF 100 1:2.8 USM Macro

Features

• Diagonal Angle of View: 24°
• Lens Construction (elements/groups): 10/9
• No. of Diaphragm blades: 8
• Minimum Aperture: 32
• Closest Focusing Distance (m): 0.31
• Maximum Magnification (x): 1
• AF Actuator: USM
• Filter Diameter (mm): 52

Autofocus lens for macro photography up to life-size (1x) magnification

Medium telephoto lens with a macro feature for 1x magnification. Fluctuations in spherical aberrations caused by focusing are suppressed, and high-quality images are obtained at all focusing distances. With eight aperture blades, good background blur is obtained even when the aperture is decreased by one or two stops. A focusing limiter which limits the magnification to 0.25x is built-in.