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

This is one of my favorite lens when it comes to shooting outdoor landscape, group shots, creative, out of ordinary shots. Our normal eyes see things at about the same as 50mm lens sees. 17mm gives really wide view and often you can create some dramatic shots with it.

As a member of "L" lens, this lens uses better glass than non L lens thus it is able to produce sharper images and gives more punch color. Build quality is excellent and has water seal that works with high end professional cameras. At about $600~$700 street price, this is a great lens to keep. There's a similar lens though. Canon EF 16-35mm f/2.8L. It's little faster and has 1mm wider advantage, but has ticket price of almost twice as much as 17-40mm, and many people will agree that 17-40mm does well.

A complementing lens would be EF 70-200mm f/4 L along with EF 50mm f/1.4 which I own both of these lens.

Thanks for reading my review.

Excellent image output. Not heavy, easy to carry. Good focal coverage especially on scenary.
Canon's L zoom lenses mostly use 77mm filter, so the filter on this lens is exchangable with other L zoom.
It's F4, so it struggles in low light. But, there is 16-35mm/2.8 L for low light, of course, with a high price tag.

This is my second Canon L lens. The first was 70-200mm f4L. I was so impressed with build quality, contrast and sharpness I immediately sold enough stuff to go out and buy my 17-40 f4L.
I absolutely can not find any reason to buy anything else in this range for quality and price.
If you need the extra f stops then you probably have or will find the extra big bucks to go out and get one of those big heavy and expensive fast lens.
I can say that I have Canon "L" lens fever.
You will need buy a filter to make the sealing feature of this lens complete.
Remember if you are only using this as digital lens with crop factor; you will not need a more expensive wide angle filter. So buy a good one. 77mm Ouch.
From the moment I put this lens on camera it has been a pleasure to use.
Viewfinder is bright and my split image screen works very well. I can't say enough about full time manual focus control for fine tuning.
If you are on the fence waiting to jump for one these I suggest you LEAP on it.

This lens is truly great for landscape and architectural shots on 5D Mark I and I am sure it would be a great performer in crop cameras. I wanted to buy the big brother, 16-35L, f2.8; but that is double the price of canon 17-40. I use this lens mostly outdoor and with high f stop so I don't need a fast lens for outdoor shots. You could use this lens indoors but must increase the ISO which still gives me excellent shots on the 5D.

I love this lens on a crop sensor for outdoor use. Most of my photography is outdoors on backpacking and hiking trips. The durability and size of the lens are perfect for such a use. Thus, for my needs the lens works beautifully. If you are planning on working in low light, without a tripod, while photographing moving objects, and don't want to use a flash 100% of the time (e.g., the wedding scene), I would consider another lens. If you want a great touring lens that you use to shoot landscapes, buildings, and other scenic views, the 17-40 f/4L might be the lens for you. I rate the 17-40L as 'Good' because it isn't perfect for every situation; however, for the price, image quality, and build, it is excellent for some situations.