Canon EF 24mm f/1.4L USM
This is a pro lens (with a pro price) with a huge max aperture of f/1.4 making it very very fast and great in low light. Multiple elements in the lens correct for distortion and abberation (spherical and chromatic). This is a great lens on the 20D because it is wide and with the 1.6x factor it makes for a pretty good portrait lens.Focal Length & Maximum Aperture: 24mm 1:1.4
Lens Construction: 11 elements in 9 groups
Diagonal Angle of View: 84 degrees
Focus Adjustment: Rear focusing system with USM
Closest Focusing Distance: 0.25m / 0.82 ft.
Filter Size: 77mm
Max. Diam. x Length, Weight: 3.3" x 3.1", 19.4 oz. / 83.5 x 77.4mm, 550g