I recently upgraded my wide angle zoom from the Canon EF 17-40mm f/4L USM (above left) to the Canon EF 16-35mm f/2.8L USM (above right). If you're a self-proclaimed gear-head like me, then you'll enjoy this article. If you're just here for the photos, there are plenty of those too!
When it comes to full frame compatible wide angle lenses, there are a lot of options for Canon shooters. Aside from the two lenses photographed above, there's also the newer Canon EF 16-35mm f/4L IS USM, which offers the advantage of image stabilization, and the soon-to-be-released Canon EF 11-14mm f/4L USM, which is a humongous lens with a humongous price tag. I can't really comment on any of those lenses, not having used them, so this article will focus on my experience upgrading to the 16-35 and some of my photos with it. This is not really a review, although you may find this article helpful if you're considering between these two lenses.
For starters, let's get one thing clear: the 16-35 is about twice the price of the 17-40, but it is not twice as good, in my opinion. That doesn't mean I regret my decision to upgrade (I got mine used, so I did not pay full retail, and I got 4 high quality filters with it - a pretty good deal!). Unfortunately, when it comes to high end camera equipment, you often pay a high premium for what amounts to a marginal upgrade.
One of the advantages of the 16-35 is the extra millimeter at the wide end. It may not seem like much, but in certain situations it will make a differences (and admittedly, in many, it will not). Indoors when you are trying to get as much of the room as you can in the shot, that extra millimeter can help.
Another thing I really like about the 16-35 is its sun stars. When stopping down the lens to about f/11 or smaller, bright lights (such as street lights or the sun) become gorgeous stars. This is the type of thing that may not make much difference to the casual shooter, but to the enthusiast or professional, it can really make a shot look special. Unfortunately, with all these sun stars comes a lot of flaring, which can be both a blessing and a curse. Technically, flare is a flaw, but I tend to think it adds character to a photo.
The main reason I wanted to upgrade to the 16-35 was because of the f/2.8. I considered the newer version with the image stabilization, but the f/2.8 adds so much versatility to this lens! For one thing, I can use this lens wide open as sort of an environmental portrait lens and still achieve some background separation (see the above photo of my cat, taken at 16mm). I speak from experience when I say that this is very difficult to do with the 17-40 at f/4. It's simply a matter of science that I won't get into for fear of boring my readers! This will hardly replace my beloved 50mm f/1.4 or 135mm f/2 lenses, which can turn a background into pure mush, but it will be nice, especially when traveling, to be able to have a wide angle lens on and be able to use it as a portrait lens without having to switch out all the time. Below is another example where I was able to achieve some separation with the lens at 35mm and f/2.8.
Another reason f/2.8 is so versatile is that it can help make night shots less noisy, which comes in especially handy for milky way photos, where shutter speeds need to be relatively fast to keep the stars from moving. I don't have any examples of this in action yet, but when I do, I'll be sure to share them.
As much as I love using wide angle lenses at their widest setting, I like to take full advantage of the zoom range. Not every scene lends itself to a super wide treatment. The above photo was taken at 29mm.
As much as I love this lens, though, there are are a few drawbacks. It is substantially larger and heavier. I was worried I wouldn't be able to stuff it into my camera bag, but that wasn't an issue. The bigger issue was the 82mm filter thread. If you don't use filters on your lenses, this means nothing to you, but if you do, you know it's a huge deal. I use a 10-stop neutral density filter, which was sized for a 77mm filter thread. By upgrading, I had to purchase a larger and more expensive filter (but then sell the smaller filter to offset it). This is what kept me from upgrading for a long time, but since I got several filters with my lens, that made the process cheaper for me, so I jumped on it.
If you're a full frame Canon shooter looking for a wide angle lens, you can't go wrong with either the 17-40 or the 16-35. I'd hate to recommend one over the other, because there is such a huge price difference. If things like an extra itty bit of wideness, nice sunstars, and f/2.8 don't mean much to you, then go for the 17-40. If those things are important to you, consider the 16-35.
All of the photos in this post were taken with the 16-35. To see even more photos I took with this lens, check out my album on Flickr. To see photos I took with my previous wide angle lens, the 17-40, check out my other album on Flickr. Both of these lenses are designed to be used on cameras with full frame sensors (such as the 6D or 5D series). If you shoot a crop sensor camera (such as a rebel or XXD series), I recommend the Canon 10-22, which I used when I shot primarily crop sensor. To see photos I took with that lens, check out this album on Flickr.