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EF 17-40mm f/4L USM

An affordable L-series ultra-wide-angle zoom lens that's ideal for both film and digital SLRs. Superior optics are assured by the use of three aspherical lens elements, in addition to a Super UD (Ultra-low Dispersion) glass element. Optical coatings are optimized for use with digital cameras. This lens focuses as close as 11 inches (0.28m), and offers both Canon's full-time manual focus and a powerful ring-type USM for fast and silent AF. It has a constant f/4 maximum aperture, and offers the choice of screw-in 77mm filters or a holder in the rear of the lens for up to three gel filters. Finally, it offers weather-resistant construction similar to other high-end L-series lenses.

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Print Specs

  • Focal Length 17mm – 40mm
  • Aperture Maximum: ƒ4
    Minimum: ƒ22
  • Angle of View 57.3° – 104°
  • Lens Construction 12 elements in 9 groups
  • Diaphragm Blades 7
  • Minimum Focusing Distance 28cm (11.024")
  • Filter Size 77mm
  • Autofocus Type Rear focusing system with USM
  • Weight 500g (1.1 lb)
  • MTF Chart

Reviewed by: Photodo
Canon 17-40mm f/4 L USM
This lens, which has become almost legendary amongst Canon users, has been around for a little while now. There are a number of new or updated contenders on the market in what has been a competitive sector. We look at how this war-horse is standing...
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Reviewed by: The-digital-picture
Canon EF 17-40mm f/4 L USM Lens Review
Because it is a very high quality but moderately-priced ultra wide angle zoom lens, the Canon EF 17-40mm f/4 L USM Lens is one of Canon's best selling lenses. The 17-40 f/4 L fills out the bottom focal length range of Canon's f/4 L zoom lens...
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Reviewed by: Pcmag
Canon EF 17-40mm f/4L USM
The Canon EF 17-40mm f/4L USM ($839.99 direct) is an ultra-wide to normal zoom lens that is compatible with Canon EOS SLR cameras. When used on a full-frame body, the lens provides an extremely wide 17mm field of view on the wide end with a 2.4x...
Read more:,2817,2403102,00.asp