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  • Writer's picturePhil Davenport

Canon EF 17-40mm f/4L USM Overview

Updated: May 19, 2021

I’m by no means a professional landscape photographer and considering I live in the glorious west of Ireland I probably should be. However as a keen amateur in this genera there is a lens I carry just in case the opportunity should arise to prove my worth.


Spanning a versatile wide-angle range, the EF 17-40mm f/4L USM Lens is a Canon L-series zoom featuring a constant f/4 maximum aperture along with a sophisticated optical design and durable construction.

Wide-angle zoom is designed for full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it provides a 27.2-64mm equivalent focal length range. Constant f/4 maximum aperture maintains consistent illumination throughout the zoom range.

One Super Ultra-Low Dispersion glass element noticeably reduces colour fringing and chromatic aberrations for high clarity and colour 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 colour neutrality when working in strong lighting conditions. A ring-type Ultrasonic Motor (USM), along with an internal focusing system, is employed to deliver fast, precise and quiet autofocus performance as well as full-time manual focus override. Rounded seven-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. In addition to the front 77mm filter ring, this lens also has a rear filter holder for up to three cut gel filters.



LANDSCAPES PHOTOGRAPHY. When your shooting the great outdoors, you often want to fit more of the scene into your composition. The 17-40 is considered a super-wide angle lens and gives you the perfect range of a super wide to moderately wide angle of view.

SMALL INTERIORS. The 17mm setting will give you the ability to shoot wide shots in cramped interior areas. Real estate photographers must use them to be able to show as much of a room as possible in each photo. The Canon 17-40 is also great for shooting a large group of people indoors where you don't have much room to use.

ARCHITECTURE. Similar to shooting landscapes, you need to show as much as you can of a large subject. Tall buildings, bridges, any large subject needs a lens to have a wide view to fit large subjects into your photograph's composition.

STRONG PERSPECTIVES. Super wide angle lenses the the 17-40 give you strong perspectives for creative photography. Objects closer to the camera appear disproportionately bigger than objects further away.

All in all this is an affordable alternative to the more expensive and more recent Canon EF 16-35 f/4L IS USM, the fact it has been around since February 2003 speaks volumes about its build, usability and performance. I can highly recommend the now classic Canon EF 17-40 f/4L USM and for those with the extra cash then of course the newer 16-35 wins on overall performance.

Product links can be found here:

Canon EF 17-40mm f/4L USM Lens

Canon EF 16-35mm f/4L IS USM Lens

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