Photo by Scott Bourne

(Canon 17-40, F/5.6 zoom extended to 37mm on a Canon 1DS MKIII)

I know this lens has been around for a while – but it’s new to me, so I decided to review it.

For a long time I had this focal range covered by a very nice Tamron lens that I used reliably. I never had any need to switch to Canon just because there’s some negative stigma attached to using third-party lenses.

But after years of very hard use, and yes some accidental abuse (this lens was used by my students during dozens of field workshops) it bit the dust.

I looked at the 16-35, but I already have access to a 14mm Rectilinear-corrected lens. That being so close to the 16, I decided to save the weight and the money and get the 17. I realize that the 16-35mm lens is probably a better choice for my 1DS MKIII, but it works well enough on the full-frame camera and superbly on the 40D body.

By the way I mention weight because it is important. As I grow older, every ounce in my camera bag is my enemy. At 1.1 lbs, this is Canon’s lightest and smallest “L” zoom lens.

I won’t go into a bunch of mind-numbing statistics about the lens. You can get those on tons of different blogs and Websites. Instead, I’ll just hit the highlights and give you my impression of the lens.

You should know I don’t have any fancy test equipment and I don’t need any. I’ve been making images from cameras for more than 35 years. My eyes are the best test bench I have.

First the basics. The lens is quiet and as you’d expect, focuses quickly and smoothly. It’s effective focal length (EFL) on a Canon 10, 20, 30, 40D, etc. is 27-64mm. Of course it is what it is on my 1DS MKIII since there is no crop factor.
My mounted 77mm B+W circular polarizing filter didn’t rotate when affixed to the 17-40. A real plus, in my opinion.

At F/4, this lens is one full stop slower than the 16-35mm “L” from Canon, but it’s also half the price.

It’s sharper at the short range than the long range and at f/5.6, it’s really sharp everywhere.

There is great lens flare protection and contrast is very good. As you might expect, there’s some mild distortion at 17mm but at about 22mm I didn’t notice it.

There is no vignetting on my 40D, but I get mild vignetting on the full-frame sensor body. The vignetting is virtually gone at f/5.6 on the 1DS.

It has a very good minimum focusing distance of 11 inches throughout the zoom range, and this lens feels solid. It’s fun to use and for around $700, is a steal when compared with other lenses in the price range.