Standard zoom is designed for
full-frame Canon EF-mount DSLRs, however can also be used with APS-C models
where it provides a 38.4-112mm equivalent focal length range.
Bright constant f/2.8 maximum
aperture affords consistent illumination throughout the zoom range and also
affords greater control over depth of field for working with selective focus
techniques.
One Super Ultra-Low Dispersion
element and two ultra-low dispersion glass elements noticeably reduce color
fringing and chromatic aberrations for high clarity and color fidelity.
Three aspherical elements
minimize spherical aberrations and distortions for improved sharpness and
accurate rendering.
Super Spectra coating has been
applied to individual elements to minimize ghosting and flare for greater
contrast and color neutrality when working in strong lighting conditions.
A ring-type Ultrasonic Motor
(USM), along with an internal focusing design, optimized focusing algorithms,
and a high-speed CPU, is employed to deliver fast, precise, and quiet autofocus
performance as well as full-time manual focus override.
Rounded nine-blade diaphragm
contributes to a pleasing out of focus quality that benefits the use of shallow
depth of field and selective focus techniques.
Protective fluorine coating has
been applied to the front and rear element to resist fingerprints and smudges
and to make cleaning these elements significantly easier.
As a member of the esteemed
L-series, this lens is sealed against dust and moisture for working in
inclement environmental conditions.
Zoom lock lever secures the
zoom position at the wide end to maintain a compact form factor and protect the
lens when not in use.