The five zoom groups make the length only 121.

5mm.

With rear focusing the lens does not change length or rotate during focusing.

Any filter effects therefore remain intact.

It also makes autofocusing quick and quiet.

Features Five zoom groupsRear focusing Specifications Weight g 540 Filter Diameter mm 58 Maximum Magnification x 0.

20 at 300mm Magnification with Extension Tube EF12 0.

260.

04 Magnification with Extension Tube EF25 0.

370.

09 Diagonal Angle of View 24 11 8 15 Horizontal angle of view 20650 Lens Construction elements/groups 13/10 Max.

Diameter x Length mm 73x121.

5 Minimum Aperture 3238 Data based on EOS models with exposures displayed in 1/2 stop increments.

It varies slightly with the EOS1N or the EOS1.

No.

of Diaphragm blades 8 Closest Focusing Distance m 1.

5 AF Actuator USM Mechanical fulltime manual focusing builtin.

Soft Case ESC17 Lens Hood ET65II Package content Canon EF 100300mm f/4.

55.

6 USM Telephoto Zoom Warranty 30 Day Warranty.

Warranty covers manufacturer s defects only.

This product is not covered by misuse of product or damage due to mishandling.