An Optical Image Stabilizer helps to minimize the appearance of camera shake by up to four shutter speed stops to better enable working in low-light conditions and with slower shutter speeds. Three distinct IS modes are available: standard single-shot mode, a panning-optimized mode, and a mode that only activates the Image Stabilizer during the exposure.

A ring-type Ultrasonic Motor (USM), along with 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.

Focus Preset function is available to quickly recall a programmed focusing position.

Focus Limiter switch lets you constrain the focusing to three different ranges to suit different applications.

A Power Focus setting is available, and allows you to electronically and smoothly adjust your focus position to suit video recording. This setting utilizes a dedicated ring in front of the main focusing ring and allows you to use one of two different focusing speeds.

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.

As a member of the esteemed L-series, this lens is sealed against dust and moisture for working in inclement environmental conditions.

Removable rotating tripod collar is included and benefits working with the lens atop a tripod or monopod.

Compatible with optional EF 1.4X and EF 2X teleconverters.

One Super ED element and two extra-low dispersion elements are featured in the lens design and help to reduce chromatic aberrations and color fringing for improved clarity and color neutrality.

Nano AR Coating II has been applied to reduce surface reflections, flare, and ghosting for increased contrast and color rendering in strong lighting conditions. This updated coating is better suited for larger, curved elements and is especially adept at minimizing internal reflections.

An XD Linear Motor system uses two separate motors, along with an internal focusing design, to provide quick, quiet, and precise autofocus and tracking performance. This design also contributes to more natural, intuitive Linear Response manual focus control and an AF/MF switch is located on the lens barrel for quick focus mode switching.

Minimum focusing distance of 9.8" suits making dynamic close-up images.

A focus hold button is present on the lens barrel for intuitive tactile control and rapid access to select programmable settings.

Physical aperture ring can be de-clicked for smooth, silent aperture switching to benefit video applications. The ring also incorporates a locking "A" position for use in automated exposure modes.

Dust- and moisture-sealed design better permits working in inclement conditions and rubberized control rings benefit handling in colder temperatures.

Fluorine-coated front and rear elements resist dust, moisture, and fingerprints and are easy to clean.

Filter holder is incorporated at the rear of the lens, within the lens mount, and accepts cut gel filters and a filter cutting template is included.

Integrated petal-shaped lens hood helps to block stray light from causing lens flare and also affords some physical protection to the front element.