.

.

Canon EF 17-40 4L USM

An "L" of a Lens

Peter Kun Frary

---

If you're particular about image quality, buy the best lenses you can afford. After all, the caliber of your images will be mainly determined by technique and lens quality, not the camera. Quality EF lenses are an investment for the future as they'll work on all EOS SLRs, film or digital.

Venetian Ceiling Detail • EOS 10D, EF 17-40 4L USM, 430EX Speedlite, ISO 100, Tv Mode (29mm, F4, 1/60).

The wide zoom--16-35, 17-35, 17-40, 20-35, et al.--has been a mainstay of pros, especially photo journalists, since the early 1990s. These focal lengths are perfect for sweeping views and shooting in tight quarters, and are easily hand holdable. However, wide zooms are a recent design innovation and have been prohibitively expensive for the best examples. Prior to the 1990s you needed a set of primes for similar coverage. Back in the day, my Nikkor 28-50 3.5 AIS was an expensive "wide" zoom (it still holds its own optically with modern zooms). Quality 17, 18 and 20 mm primes were and still are expensive.

Construction & Feel

The optical design and antireflection coatings of today's zooms have evolved to the point the best examples rival prime lenses. Unfortunately, most consumer zooms are cheap plastic affairs with silk-screened symbols and coarse zoom and focus action. Canon's EF 17-40 4L USM bucks this trend and combines modern optical design and AF with a nod to the durable construction and silky zoom and focus action of yesteryear. At $650, it's more affordable than the EF 16-35 2.8L USM ($1300), but offers similar build and optical quality.

EF 17-40 4L USM • Constant aperture, internal zoom and focus, weather seals and compact design leave little more to be desired in a wide zoom.

The hybrid metal and plastic construction (polycarbonate barrel) and quality components make the EF 17-40 4L USM tough as nails, but a lightweight 475 g (16.8 oz). Plus, the moisture and dust seals, including a rubber O-ring on the lens mount, make it a great choice for jungle and beach shooters. Canon recommends the use of an UV filter for total weather sealing (the front element moves slightly during zoom). This lens feels solid and well made.

The EF 17-40 4L USM is a classic two-touch design: focus ring near the end of the barrel and zoom ring near the mount. Once you get used to this design, handling is nimble and decisive. Both zoom and focus mechanisms are internal so there is no extension of nested barrels. Moreover, internal mechanisms are less prone to sucking in dust than front extension designs. Unlike most AF lenses, the manual focus ring is large, ribbed, rubberized and nearly as smooth turning as the manual lenses of yesteryear. Plus, the flat black finish is elegant and the overall appearance similar to the EF 16-35 2.8 USM.

Sunlight in Trees • Roundtop Drive • EOS 10D, EF 17-40 4L USM

Auto Focus

This lens sports a ring-type USM (Ultrasonic Motor) that drives an internal lens group and, thus, AF rips. The front element does not rotate nor does the barrel expand or contract during focus and zoom operations. The motor of the EF 17-40 4L USM is silent during AF. It has FTM, allowing you to manually focus without switching out of AF mode. If you prefocus manually, the distance window in meters and feet is extremely useful.

The zoom's AF worked flawlessly on my EOS 5D, 3, Elan 7E, 10D, Elan, IX, A2 and 20D bodies. That is, AF is fast, accurate and decisive. Moreover, the maximum aperture of F4 is sufficient to fully enable the center AF cross sensor on all six EOS bodies. Unfortunately, this lens isn't well suited for older pro EOS cameras, e.g., EOS 1 or 1N, as the maximum aperture of F4 is too slow to fully enable their cross AF sensors.

FDNY • Las Vegas • EOS 20D, EF 17-40 4L USM, F4.

The filter size is 77 mm, making filters expensive and difficult to share with Canon consumer lenses. The EF 70-200 2.8L IS USM and EF 24-105 4L IS USM are among the few Canon lenses to share this filter size and sport a complementary zoom range, making for an excellent albeit expensive combo. The clearance from the edge of the front element to the filter threads is huge and, subsequently, normal thickness filters such as my Hoya Super HMC UV do not vignette on full frame (36 x 24 mm).

Drummer Boy • Moana Surf Rider Hotel, Honolulu, Hawaii • EOS 10D, EF 17-40 4L USM, F4.5.

Optical Performance

As expected, the EF 17-40 4L USM is very sharp and contrasty, a clear level above my EF 24-85 3.5-4.5 USM (a decent lens). The constant F4 aperture is a big plus for hand meter users and those that prefer manual or aperture priority exposure modes. Another advantage of this lens over consumer zooms is it exhibits little image degradation at large apertures or at the long end. In other words, it's sharp wide open and across the zoom range. Stopped down to F8 or F11, images from this lens and the EF 24-85 3.5-4.5 USM are nearly indistinguishable. Nevertheless, top image quality wide open is essential if you frequently hand hold your camera.

The contrast and snap of this lens is apparent even through the viewfinder. After all, there's some exotic glass in there, e.g., 1 UD and 2 aspherical elements. The short end, like most wide zooms, shows considerable barrel distortion. The long end has a small amount of pincushion distortion. For most use, distortion isn't a problem. However, architectural and product photographers should stick with primes.

Flare is extremely well controlled for a zoom. With full frame coverage (e.g., 35 mm film), some flare and ghosting may occur with bright sunsets. Smaller formats, e.g., APS film and APS-C digital, exhibit virtually no flare or ghosting. You should use the huge lens shade (EW-83E) to protect the lens and help keep flare in check.

Sunset at Roundtop • EOS 10D, EF 17-40 4L USM: 40mm, F4

Cons

There aren't many cons about this lens, so I'll have to nitpick. The included hood is bulky and doesn't afford much protection. It scares people and blocks the popup flash at all focal lengths. With the hood removed, the EOS 10D's popup is fine from 24-40 but is blocked at wider settings. Surprisingly, it does not block the 20D popup at any focal length as long as you leave the hood off. In terms of popup blockage, every camera model is different so test before an important shoot.

Of course, it's fine with an external flash, although some flash units may not cover the widest focal lengths on full frame cameras. For example, 420EX coverage only extends to 24mm with full frame EOS bodies, e.g., EOS 3 or 1Ds. In contrast, the 420EX Speedlite is fine at all focal lengths with 1.6x bodies such as the EOS 10D or 20D.

This is an incredible ultra wide zoom on my EOS 3 and 5D but a bit of a yawn on cropped frame bodies such as the EOS 10D or 20D. Why? The cropping factor essentially makes it into a boring 27-64 zoom. I'd like more reach for a walk around zoom. However, a 17-40 zoom is a thrill through the big, bright viewfinder of an EOS 3 or 5D. I just have to be careful not to include my feet in the photographs!

Off to Save the World • EOS 40D, EF 17-40 4L USM, Elan & Tamrac System 6 Bag

Final Words

If you shoot architecture or mainly use the short end of a wide zoom, buy a wide prime. Primes are smaller and have much less distorion. If you like to hand hold in murky light, buy a wide and fast prime. However, if you need the versatility of a wide zoom, this is among the best. The EF 17-40 4L USM has similar build and optical quality as the famous EF 16-35 2.8L USM, but at nearly half the price, weight and shy a F stop. Most pros will buy the EF 16-35 2.8L USM as the extra stop may mean the difference between getting a paycheck or not.

For discriminating hikers, travelers and serious amateurs this zoom deliverers quality without breaking their shoulder (and bank) and can take the knocks they dish out. Highly recommended.

Roundtop Drive View • EOS 10D, EF 17-40 4L USM, F7.1

Specs

Focal Length: 17-40 mm

Aperture: F4 to 22

Lens Construction: 12 elements in 9 groups with 1 UD and 2 aspherical elements

Min. Focusing Distance: .28 m/.92 ft

Diameter & Length: 83.5 x 96.8 mm/3.3 x 3.8 inches

Weight: 475 g/16.8 oz

Included Accessories: EW-83E Lens Hood and Storage Bag

Cost: $700

Wedding Guitarist • EOS 50D & EF 17-40 4L USM (32mm)

More Images taken with the EF 17-40 4L USM (click to enlarge)

 1/17/2004 • Updated 2/13/2011

.