【Huong様専用】Canon EF17-40mm F4L USM
Canon EF 17-40mm f/4L USM | Canon U.S.A., Inc.
It has a constant f/4 maximum aperture, and offers the choice of screw-in 77mm filters or a holder in the rear of the lens for up to three gel filters. Finally, it offers weather-resistant construction similar to other high-end L-series lenses. Technical Specifications Main Unit Spec Focal Length & Maximum Aperture 17 - 40mm; 1:4 Lens Construction