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The Canon EF 17-40mm f/4L USM is one of the Canon L series lenses, although it is one of the more affordable L lenses with professional grade optics by the use of three aspherical lens elements, in addition to a Super UD (Ultra-low Dispersion) glass element. It is often compared to the EF 16-35mm f/2.8L USM, but at half the price, although one less F stop. I paid $700 for this lens with lens hood and pouch at B&H in February 2004. It is labeled by Canon as an ultra-wide zoom lens, but when used with a Canon EOS 10D, it effectively becomes 27-64mm because of the 1.6x crop factor, which really puts it in the standard zoom category for this particular camera. Even so, I find this lens to be perfect for landscape, architecture, and other situations requiring a wider angle of view. It is well constructed, light (1.1 lbs.), and has moisture and dust seals. In addition, it has a rubber O-ring on the lens mount. Canon recommends a filter to make it truly dust resistant since the front element does move when zooming. One drawback is the expensive 77mm filter size it takes. It does have the ability to use gel filters in the slot on the rear of lens. The lens can focus as close as 11 inches and comes with Canon's full-time manual focus and ring-type USM for fast and silent auto-focus. The 17-40mm is very sharp and has great contrast wide open and across the zoom range, although it has been reported that there is some distortion wide open, but I havent noticed it coupled with the 10D. One other minor noticeable fault is when using this lens with the lens hood installed, the hood will create shadows when using the pop-up flash on the Canon EOS 10D, but is not a problem when using an external flash. Overall, this lens is fun to use, it is fast and sharp, and it is truly an incredible lens for the price. I highly recommend it.


Professional L-Series lens
Low relative cost
Sharpness and contrast
Fast and silent focusing
Weather and dust resistance
Light and well constructed


Awkward lens hood
Large and expensive filters
Some distortion

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by SandShark See Profile edited by tmpchaos See Profile
last modified: 2004-06-27 17:29:10