- Lens construction: 18 elements in 15 groups
- Diagonal angle of view: 34°-12°
- Focus adjustment: Inner focusing system with USM
- Closest focusing distance: 1.5m / 4.9ft
- Zoom system: Rotating type
- Filter size: 77mm
One of the finest telephoto zoom lenses in the EF line, comparable to a single focal length lens. It has four UD-glass elements to correct chromatic aberrations. The newly designed multiple zoom groups for inner focusing bring high image quality throughout the entire zooming range. Compatible with Extender EF 1.4x and 2×.