Canon EF 17-40mm f/4L USM Lens
This lens focuses as close as 11 inches (0.28m), and offers both Canon's full-time manual focus and a powerful ring-type USM for fast and silent AF. 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.
- EF-Mount Lens/Full-Frame Format
- Aperture Range: f/4 to f/22
- One Super Ultra-Low Dispersion Element
- Three Aspherical Element