Testing Canon EF 17-40mm f/4L USM Lens

Posted: November 24, 2011 in Blog
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As I wrote in my last article, I’m thinking about buying a new lens, Canon EF 17-40mm f/4L USM. As a canon guy, their rep and photographer I know what it has and hasn’t also how it performs. But there isn’t anything better to try it out on your own. And so I decided to borrow this lens from my boss, had it for two days and here is my review. Just had a small issue with front-focus but it didn’t affect 98% of my images.


Build quality

When you’re buying an L-series lens you expect nothing less than great quality and performance. Lens itself is very light, weight is just around 500 g, and it makes it ideal to carry around. Also it isn’t so big. Just a bit bigger than my 85mm f/1.8. Of course it has metal mount, big front element, weather sealing and resistance, barrel build from metal. Only front side isn’t sealed but you can fix it by putting on a UV filter. If you want to do it, just be sure to put a SLIM type otherwise you’ll get some vignetting. Maybe not so big on APS-C but I’m sure you’ll notice it on a full-frame body. Fits great in hands and easy to handle.

Image quality

If I had to use just one word I’d say “superb”! Because a bad weather here in Czech republic during whole testing and my limited camera I had to shoot wide open @f/4 and use high ISO, most of the time somewhere around 800 or 1600 which is maximal limit for my Canon EOS 450D (Rebel XSi). Noise was problem but that wasn’t caused by lens but by my camera. Images were very sharp with enough depth of field (I didn’t sharpen any of photos I took). Most of the time everything was in focus, you had to get really close to get blurred background. What about chromatic aberation? Well … there were few of them in corners where was a big contrast difference. To be honest, this made me thinking how this lens will perform on a full-frame body because my APS-C sensor is using just the middle part of lens’s optic which is the best. Sharpness in corners is more than OK. I didn’t get any other optical issues.

Vignetting sample

Typical problems for wide-angle lenses

As a Canon rep I get question “Does it have barrel distortion?” a lot. Yes, images are distorted a bit in wider focal lengths. But this is typical for any wide-angle lens and if you don’t want it, get that special Canon EF 14mm f/2.8L USM. It is corrected for distortion. Anyway you can notice some distortion but you won’t care about it too much.


Paladium Gate

I’m more irritated by depth of field. If you get super close to something, you’ll get nice bokeh. Otherwise everything will be in focus. I love shallow DOF and having that foreground and background in focus at the same time makes the image look a bit weird for me. But also this is common for all wide-angles.

4M Management - 3 watching, 1 working

Is it a lens for me?

A hard question I’ve been thinking about since I made the first picture. As a people/nature/landscape photographer it is a must to have good wide lens. Also as someone who is shooting HDR I need good quality because if I get any optical issues like flare or glare it will multiply by the number of images used for merging into final HDR image. When I’m out with my 28-70mm I’m shooting most of HDRs in Prague up to 40mm of focal length so I could use this lens for it.

What drives me nuts? No DOF! Why do I love my 70-200? Why do I love my 85? Because the sharpness? Yes! Because the construction? Yes! But most of it because shallow DOF and with it I can isolate my subject from background, foreground or anything! Here? Well if you can get close enough, you can get some isolation. So is it good for street shooting? I suppose it wouldn’t be my first choice … on the other hand it’s so light and small …

Caught in a Fence

I thought I’ll know by Friday if I buy one of those or not. But now I’m just a Canon guy with some photos and messy brain. Don’t know how much time it will take, maybe I’ll just buy a new laptop or go somewhere on holiday and make few awesome images.

And here is one of my favorite images from last two days.

Caffe Restaurant


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