The EF 17-40mm f/4L USM Lens from Canon is a
high quality "L" series wide angle zoom lens for full frame and APS-C
size DSLR cameras. It combines one high-precision molded glass
aspherical element and two replica aspherical lenses to achieve the
extended zoom range, while also correcting for common aberrations that
arise during zooming. A Super UD (Ultra-low Dispersion) glass element
minimizes the chromatic aberration of magnification which tends to occur
with wide-angle lenses, to help eliminate color bleed along the edges
of the subject and achieve high image contrast and resolution.
minimum focusing distance is just 11" (28cm) throughout its entire
range of focal lengths, which makes it very useful for close-up work.
All of the focusing and zooming action is done internally, with no
changes in the size of the lens. Its ultrasonic autofocus motor enables
smooth and silent autofocus action and manual focus override in One Shot
AF mode allows precise manual focusing without switching into MF mode.
only uses lead-free optics to help the environment, and features a
circular diaphragm for improved background blur. The housing is water
and dust resistant to help ensure reliable performance for both
professionals and enthusiasts. Like many "L" lenses, it uses 77mm
filters, but also has a rear gelatin filter slot behind the lens mount
that can hold three gel filters.
This lens is a Canon 'EF' series
lens, indicating it is for use with full-frame cameras. However, it also
works with APS-C format DSLRs and offers a 35mm focal length
equivalence of 27-64mm, making it an ideal medium-aperture standard zoom
77mm Lens Cap
Rear Lens Cap
EW-83E Lens Hood
Canon LP1319 Lens Case
Canon One Year USA Warranty