Canon EF 17-40mm F/4.0 L USM Lens

The Canon EF 17-40mm f/4L USM Lens is a great great lens. That's it. You can stop reading now if you want.

It's the lightest L series lens that Canon produce and with its high quality glass it produces super sharp images and the silent focussing is near instant thanks to the ultrasonic motor. The lens elements are enclosed in weather sealed body coupled with a beautiful smoothness of touch to the zoom and focus rings.

I guess the other stand out features is the price. It's nearly half the price of 16-35mm f2.8 and I have to be honest having used both I didn't miss the extra 2 f stops. Unless you are shooting in extremely low lighting conditions this is the lens to go for. As for distortion and chromatic abberation you will be hard to pushed to find any (particularly if you are on a x1.3 or x1.6 sensor).

If there is something that is missing it is a macro label on the side of the lens body. With a minimum focussing distance of only 28mm you can actually get some really great close-ups.

So there you have have it. It's got a great focal range, is built like a tank, is sharp as a needle and weighs almost nothing. In short, every camera housing should have one.

Designed a decade ago, it is probably the best value for money ultra wideangle for Canon full frame dSLRs, and an excellent all round lens for APS-C format cameras. The colours are captured rich and vibrant and the images are contrasty. This is also a great lens to capture lovely 14-bladed sunstars, which helps a lot with landscape photography. Interior shots are also an easy task with one of those. Finally, the weather sealing helps with shooting in adverse weather conditions.

It is advisable to shoot at f/11 or higher and focus to the infinity in order to achieve the best corner sharpness in landscapes * on full frame cameras * , while APS-C users can pretty much shoot wide open. The lens is certainly no match for the vastly superior Zeiss 21mm f/2.8 prime or even Canon 16-35mm f/2.8 II, however it is priced well below the alternative products. I use mine mainly on tripod for landscapes and real estate; I pick my 24-70mm f/2.8 for anything else.

On APS-C cameras it is nice and sharp general purpose lens, however one may wish to also consider 17-50/55mm f/2.8 alternatives.

I bought this for my new Canon 50D, I previously had a Tamron 18-50 mm f2:8 which I have been very impressed with. Alright I have lost 1 stop of light and some of the focal range 40-50 but I am very impressed with the build quality and sharpness of the Canon lens. It is quieter and faster in the AF. I would also say that the Canon has a greater contrast making it appear sharper.
The Tamron has produced some great prints but this new breed of cameras with increased pixel density means that lenses that were great in the 20/30/40D show their limitations on the 50D.
Because of the APS size sensor there are few choices in a wide angle equivalent to 28 mm on 135 format so if you buy a 50D be prepared to part with some serious money to get lenses that will extract the maximum from the camera sensor.
This is the "budget" lens for this purpose otherwise expect to pay about £700 for the 18-55 mm f2.8 EFS, but remember if you go full frame (5D) you will have to get rid of the lens as well. The 17-40 covers full frame so it remains a keeper even if it then becomes very wide.
I have a 70-200 mm F4 L (non IS) and that has always been my favorite lens up till now, but it has some serious competition. Both lenses fell great, smooth zoom, full time manual focus (you can make minor changes without going to MF) and metal construction just like it used to be.

Having got a Canon 30D with kit lens I wanted to upgrade immediately. The kit lens was the old non-IS version, and not up to much. Initially I forked out for the 17-85 IS USM EF-S lens but was quickly very disappointed with the results and the build quality of the lens. After all, I had sold out of a very decent Pentax set-up and was struggling to find anything to match the quite affordable Pentax DA 16-45 f/4.

After reading a LOT of reviews and posting a lot of questions on various digicam forums I went for the 17-40L. Although the reach of the lens wasn't as good as others, the image quality, colour saturation and relatively low CA, not to mention the build quality, was a winner for me. I picked up a well used (with a broken distance scale window) for around £330.

Build quality IS excellent, but heavy. At this weight and size some would imagine it should be a far longer-reach lens. The 77mm thread can prove to be expensive for filters, but not if you shop around. I also love the image quality and the fact it's a constant f/4 lens. The reach isn't an issue for me - I shoot a lot of landscapes and mostly use the wide end of the lens. Others will find it is too limiting.

In conclusion, get this lens at a decent used price and you won't regret it. You're getting L quality (with the coveted red ring), weatherproofed build quality and excellent image quality combined with a constant f/4 aperture. The only negative is the weight and the reach - but if you're looking at the 17-40 you already know that anyway.

Most of my recent photos have been taken with the 17-40L (and the 50mm f1.8). If you want to look at some real-life shots using this lens feel free to take a look at www.flickr.com/photos/paultoml​in - nothing award winning but it gives true, real-life examples of what to expect from this lens.

This lens has a superb build quality as you would expect from a Canon L series lens. I personally chose this lens as I run full frame camera bodies both film 1Nrs and digital 5D mk2 as such can make full use of the wide angle lens. Those who use cameras's with sensors that are smaller might find this is not wide enough for them but the results you can produce from the lens are top quality and those who are lucky enough to be able to make full use of it doing landscapes or buildings / street work you would be mad to miss adding this lens to your bag as a general wide angle lens it should be first in the kit bag behind the body.