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