FOCAL LENGTH & MAXIMUM APERTURE: 70-200MM 1:2.8;?LENS CONSTRUCTION: 23 ELEMENTS IN 18 GROUPS;?DIAGONAL ANGLE OF VIEW: 34?-12?;?FOCUS ADJUSTMENT: INNER FOCUSING SYSTEM WITH USM;?FILTER SIZE: 77MM;?CLOSEST FOCUSING DISTANCE: 1.3M/4.3 FT;?ROTATING TYPE ZOOM SYSTEM