The EF 17-40mm f/4L USM Lens is an ultra-wide-angle lens producing stunning clarity in a range of focal lengths. Its compact, lightweight body makes it an ideal travel companion - suited to interiors, architecture and landscapes, fitting more in the frame without the need to step back. Produce consistent exposures with the large f/4 aperture over the 17-40 mm zoom range and create softer background blur with a 7-blade circular aperture diaphragm. Part of the Canon professional L-series flagship range, its designed for robust handling and resistant to dust and moisture.