Canon EF 17-40mm f4L USM#
Canon’s wide-angle L-series zoom. On APS-C bodies it covers 27–64mm equivalent — a useful wide-to-normal range. On full frame it’s a genuine ultrawide. Weather-sealed magnesium alloy barrel, ring-type USM motor, and constant f/4 aperture. The second most-used lens in the library (7,933 photos).
Compatibility#
| Body | Notes | Photos in library |
|---|---|---|
| Canon EOS 7D | EF native | 4,666 |
| Canon EOS 40D | EF native | 3,267 |
EF mount — compatible with all Canon EF/EF-S bodies (full frame and APS-C). On APS-C: 27–64mm equiv.
Key Specifications#
| Attribute | Spec |
|---|---|
| Focal length | 17–40mm (27–64mm equiv on APS-C) |
| Maximum aperture | f/4 (constant) |
| Optical construction | 13 elements in 9 groups (3 aspherical, 1 UD) |
| Aperture blades | 7 (rounded) |
| Minimum focus | 28 cm |
| Filter thread | 77mm |
| AF motor | Ring-type USM |
| Stabilization | No |
| Weather sealed | Yes (L-series) |
| Weight | 500g |
| Dimensions | 83.5 × 96.8mm |
| Year | 2003 |