Canon EF-S 17-55mm f/2.8 IS USM Autofocus APS-C Lens {77}

Canon's f/2.8 constant-aperture standard zoom built for APS-C DSLRs.

The 17-55mm range on an APS-C sensor translates to a 27.2-88mm equivalent, covering wide-angle environmental work through short telephoto portrait distances without a lens swap. That constant f/2.8 aperture across the entire zoom range is what separates this lens from the kit alternatives, you get the same exposure and depth-of-field control at 17mm as you do at 55mm, which matters when light changes fast.

The optical design uses Ultra-Low Dispersion glass alongside aspherical elements to keep chromatic and spherical aberration in check across the zoom range. Super Spectra coatings on individual elements suppress flare and ghosting when shooting into bright sources. The combination means contrast holds up in difficult lighting than falling apart at the edges of the frame. Image Stabilization adds a meaningful safety margin for slower shutter speeds, and the Ultrasonic Motor autofocus is fast and quiet enough for event work where noise draws attention.

At 77mm filter thread, this is a serious piece of glass built around a serious commitment to APS-C shooting. If you're running a Canon APS-C body and want a single lens that handles most of what a working day throws at you, this is the one to build around.

Who It's For

Wedding and event photographers working Canon APS-C bodies get a lot out of the f/2.8 constant aperture and IS combination, dim reception halls and fast-moving subjects are handled by the same lens. Documentary and street shooters benefit from the 27.2-88mm equivalent range covering candid wide shots through compressed mid-distance framing. Portrait photographers get usable subject separation at f/2.8 on a 55mm equivalent without switching glass. Travel photographers who want one body, one lens for a full day's shooting will find the focal range covers most situations without compromise.

Key Features

• Constant f/2.8 maximum aperture across 17-55mm zoom range
• 27.2-88mm equivalent focal length on APS-C sensors
• Ultra-Low Dispersion glass and aspherical elements reduce aberration
• Super Spectra coating suppresses flare and ghosting
• Image Stabilization provides up to three stops of shutter speed safety
• Ultrasonic Motor autofocus for fast, quiet operation
• 77mm filter thread

FAQ

What's the real-world focal length on an APS-C body?

27.2-88mm equivalent. That's wide enough for environmental shots and tight enough for head-and-shoulders portraits without switching lenses.

Does the f/2.8 aperture stay constant throughout the zoom range?

Yes. You get f/2.8 at 17mm and f/2.8 at 55mm - no stopping down as you zoom, which means consistent exposure and depth-of-field control.

How much does Image Stabilization help?

It buys you roughly 3 stops of shutter speed safety, so you can shoot at 1/15th instead of 1/125th in low light. Useful in event work where you're moving between venues.

What optical elements control aberration?

Two Ultra-Low Dispersion glass elements and three aspherical elements minimize chromatic and spherical aberration across the zoom range. Super Spectra coatings on individual elements keep contrast high in bright light.

Is the autofocus fast enough for fast-moving subjects?

The Ultrasonic Motor is quick and silent, making it suitable for event and documentary work. Not designed for professional sports tracking, but it handles most daily situations.

What filter size do I need?

77mm. Standard thread size, so you can share filters with other lenses if they match.