- Compatible with All Canon DSLR Formats
- L-Series Lens – The Best Canon Makes
- Super Wide Angle Zoom Lens
- For Film or Digital SLR Cameras
- Uses 3 Aspherical Lens Elements
- Uses Super UD Glass
- Water and Dust Resistant
- Internal Zooming and Focusing
- Circular Aperture Diaphragm
- Accepts 77mm Filters
While an excellent ultra-wide zoom lens for film SLR cameras, the Canon EF 17-40mm f/4L USM Lens is especially well suited for use with EOS digital SLR cameras, which usually have an imaging sensor size smaller than the 35mm format. When used with such digital SLR cameras, the 17-40mm focal length range gives an angle of view approximately equivalent to that of a 27-64mm lens upon 35mm cameras, making it an ideal medium-aperture standard zoom lens.
The EF 17-40mm f/4L USM, like all of the Canon “L” lenses, delivers optical performance equal to similar fixed focal length lenses, with silent, high-speed focusing. Distortions and aberrations are remarkably small for a lens of such amazing capability. It combines 1 high-precision molded glass aspherical lens and 2 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.
The 17-40’s 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 of the size of the lens. It 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.
This lens is a Canon ‘EF’ series lens, indicating it is for use with full-frame cameras. It works equally well with APS-C format DSLRs.
- An autofocus super wide angle zoom lens for both film and digital cameras
- Produces 27-64mm equivalent focal length with “APS-C” size digital EOS SLR cameras (such as the EOS 20D, EOS 30D, EOS Digital Rebel, EOS 50D, etc.)
- Uses 3 aspherical lens elements and Canon Super UD ultra-low dispersion glass
- Provides professional levels of moisture and dust resistance
- Internal zooming and focusing
- Circular aperture diaphragm for better, more natural looking background blurring
- Accepts 77mm filters, as well as gelatin filters upon the rear of lens
The Canon EF 17-40mm f/4.0L was announced back in February 2003 as a lightweight ultra wide-angle zoom and has since become a bit of a classic lens for owners of Canon EOS digital and film SLRs.
Its ultra-wide focal range delivers spectacular coverage on film or full-frame digital SLRs, although it’s sufficiently wide to also be considered as a general-purpose zoom on APS-C bodies like the EOS 30D and 400D / XTi. When fitted to an APS-C body, it delivers a range equivalent to 27-64mm, and while the long-end is clearly shorter than general purpose EF-S zooms, it does have the advantage of being compatible with a full-frame body should you wish to upgrade in the future.
This article reviews the full frame performance of the Canon EF 17-40mm f/4L lens. My intented use of the lens is for landscape photography with a Canon EOS-1Ds camera. The EF 17-40mm f/4L lens (left panel) is a very sharp, high contrast zoom lens with performance characteristics that often match and sometimes exceed those of quality prime lenses at wide angle. Performance drops off slightly in the corners at 35mm, but otherwise this lens is an outstanding performer at a very good price ($670, US Gray Market).