Canon makes two high-quality wide-angle zoom lenses for full-frame
cameras, the 17-40/4L reviewed here and the
Canon EF 16-35mm f/2.8L II USM, (buy from Amazon). In the digital era, the 17-40 has
been overlooked to some extent. It isn't wide enough to be dramatic
on a small sensor camera such as the popular Rebel series. It doesn't
offer enough of a cost savings over the 16-35/2.8L to be interesting
to the folks buying the full-frame sensor cameras. Our prediction is
that this lens will come back into its own when Canon brings the cost
of a full-frame body down below $1200. Until then, anyone with enough
money for a 5D will probably simply buy the 16-35.
The lens design is of low complexity for a zoom, with 12 elements of
glass arranged in 9 groups; Canon's f/2.8 prime wide-angle lenses
typically include 10 elements of glass. Three of those elements are
aspherical, which improves image quality and reduces the number of
elements required. Thus, contrast can be as high and flare as
well-controlled as with a simpler prime lens. Distortion will be
a little higher.
Maximum magnification is 0.24x at a distance of less than one foot.
With a full-frame camera, the smallest object you can photograph
is roughly half the size of an 8.5x11" (A4) piece of paper.
Like all L lenses, the 17-40/4L is ruggedly constructed and resistant
to water and dust. The included EW-83E lens hood bayonets onto the
exterior of the lens, leaving the 77mm filter and lens cap threads
free. The 17-40 incorporates a ring USM motor, which enables
"full-time manual focus", even when the camera/lens are set to
autofocus. This is very useful when using Custom Function 4
on an EOS body, which moves autofocus to the exposure lock button on
the rear. You can focus manually if desired and, at any time, push
the rear button to give yourself a shot of autofocus.
Weight is 500g, which balances well with Canon's mid-priced bodies.
The medium-speed prime lenses are much lighter, however, e.g., only
185g for the 28/2.8.
The most likely alternative to this lens is
Canon EF 16-35mm f/2.8L II USM, (buy from Amazon), which is somewhat heavier (640g) and
twice as expensive. The highest quality alternative to any wide-angle
zoom lens is a bag of prime lenses:
It isn't lighter than the 16-35/2.8L. It isn't better quality than
the 16-35/2.8L. It isn't dramatically wide on the small sensor
cameras. However, if you want a high quality wide-angle zoom with a
medium weight and a medium aperture, the 17-40/4L is an excellent
When Canon comes out with an inexpensive full-frame digital body, this
lens will be part of a great traveling kit:
22m, f/7.1, ISO 100, 1/100th of a second (folks move pretty slowly in
their caps and gowns on a hot summer day). The wide angle shows the
newly minted PhDs (falcons and PhDs are the only animals that are
regularly hooded) and the background of MIT's Killian Court.
24mm. With street photography, you
need to lift the camera, push the shutter release, and put it down
with a smile before people start throwing stuff at you. Chinatown,
Manhattan. ISO 200 allowed settings of f/5.6 and 1/250th. Stopping
down from f/4 increased the depth of field enough to cover focus
errors. The faster shutter speed freezes camera shake and/or subject
17mm. One of the joys of street photography is serendipity. I set up
for a photo of this father, proud that he doesn't have to pay MIT
$50,000 per year anymore, and the hipster skateboards through. The
shutter speed of 1/80th wasn't fast enough to freeze the skateboarder,
but maybe that is for the best since the blur suggests motion.
17mm. Everyone has long legs at 17mm. Downtown/Wall Street Heliport. Parking is about $50 per hour.
Two similar images of a handball game. It is tough to choose between
these photos because they are both so bad. "If your pictures aren't
good enough, you aren't close enough." Getting closer in this
situation would probably have resulted in a serious contusion.
Image at left: 17mm.
Image at right: 40mm. I wish that the final ear in the frame had a
mobile phone held up to it, but that's why street photographers throw
out 99 percent of their images.
36mm. There is something about a gun shop in Manhattan that makes a
photo interesting even at a boring point-and-shoot camera focal length.
17mm. Even at f/9, the background is not within the depth of field,
which concentrates attention on the foreground circle of photographers.
17mm, f/5, 1/800th, ISO 200. Helicopters fly pretty low and the downtown Hartford, Connecticut airport
is pretty big. The 17mm wide end of this lens enables the relationship
among the airport, the river, and the highway to be