April 1, 2020

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

The Canon EF 17-40mm f/4L USM lens has been in my bag since nearly the beginning of my career. As a wedding photographer, my goal is not only to capture beautiful moments, but to tell the full story of a wedding day by documenting context and events in both large and small spaces.  This lens not only allows me to capture the full context of events, but it allows me to capture large group photos, and to get in on the action when there is very little space. This ultra wide-angle lens is lightweight, extremely well-built, and optically sufficient. In this review, I will share five things I love about this lens, and three things to be aware of.

Five things I love:

1. First off, I love the build quality of this lens. Canon’s professional line of lenses are called “L series” lenses. Distinguished by their red ring, they are extremely durable and built to last a long time. The Canon EF 17-40mm f/4L lens fully lives up to its “L” designation. Its barrel is made of metal, and the glass has not scratched nor has the AF motor worn out in all my years of using this lens. I love how fast the zoom ring response is. To zoom from 17mm to 40mm, I only have to rotate the zoom ring 1/6 of a full rotation. That means if you are using it to capture action, you can move the lens in and out quickly to capture movement or different perspectives. The one challenge is that the lens does pick up some sun flare when shooting in direct sun.  Even when using the hood that the lens comes with, it is difficult to shade the entire lens given how wide the field of view is.  That said, overall, I couldn’t be happier with the build.

2. I also love the speed of the Canon EF 17-40mm f/4L lens’ auto-focus.  For fast-paced events and weddings, it is more than fast enough. While it’s unlikely that one would use it primarily for sports photography, it certainly could keep up. It also focuses very quietly, hardly making any noise, which comes in handy when photographing quiet ceremonies. 

3. Its size is actually one of my favorite things about the lens and is also why I have not yet upgraded to the Canon EF 16-35mm f/2.8L III USM lens. My primary use for this lens is for photographing dances. I put the lens in manual focus mode and set the focus to around 3-5 feet. That way the lens does not have to try and figure out focus in the dark. I typically compose these images using a “down” angle both so that it portrays people in a more flattering angle, and so that it also allows me to include more people in the shot. To do this, I usually hold my camera up above the crowd with one arm over my head. If I were to do this using a heavy 2.8 lens, my wrist would wear out but the end of the dance. Thus, the size and weight of the Canon EF 17-40mm f/4L lens is ideal!

4. The lens’ reasonable price is definitely a plus. Back when I was just starting out as a professional photographer, and ready to begin investing in my first L series lenses, I reached out to a pro photographer I have always held in high regard.  Geneoh recommended the Canon EF 17-40mm f/4L USM lens noting it was one of the cheapest, but most useful, Canon lenses. He was spot on. For an investment of only about $650, you get a long-lasting, durable, great optic lens that is useful in countless scenarios. The Canon EF 16-35mm f/2.8L III USM version costs closer to $1,900.  While this lens would let in more light in low-light situations, as well as create more background blur, I am typically using the lens in conjunction with a flash, thus, neither of those things matter in my case, and certainly wouldn’t justify the $1,250 difference in cost.

5. The Canon EF 17-40mm f/4L USM lens‘ wide field of view is the number one reason I purchased the lens. Prior to owning this lens, I owned a Canon EF 24-105mm f/4L IS II USM lens. Though it was a very versatile lens, the problem was that I kept finding myself in situations where 24mm simply wasn’t wide enough. For example, when photographing weddings in the city among the high-rise buildings, there were often times when I was unable to back up far enough to capture the full view of the venue.  I needed a lens that I could stand across the street or just a few feet away and still be able to capture the full building. Second, I needed a lens that allowed me to take large group photos in small spaces. It is not uncommon to be asked mid-reception to take a photograph of the couple with their full extended family, college friends, sorority groups, or coworkers. 17mm has always been wide enough to fit groups in, even when standing in a small corner of the reception space. While these aren’t usually the most artistically captured photos, the lens allows me to capture the group and to preserve the moment of when they were all celebrating together in one place. Lastly, I use the 17mm focal length for dance photos. The wide angle allows me to get right in close to the bride and groom while they are dancing and capture them and their wedding parties having the time of their lives. If I were to try and do this from across the room, not only would there be guests’ bodies blocking them, but the “feel” or emotion of the image would be completely different.  I want dance images to allow the viewer to feel that they are right there in the middle of the action all over again!  

Three things to note:

1. First, the Canon EF 17-40mm f/4L USM lens‘ images tend to be soft on the edges. As with most wide angle lenses, as you get closer to the edge of the photo, the sharpness of the image will get softer. The center of the image will still be sharp, which is what matters most, and as long as the subjects aren’t composed in the corners or edges of the shot, the soft edges aren’t a huge deal.  Stopping down to f/8 will also help the sharpness of the image. 

2. Another thing to be aware of is the lens’ AF accuracy. When I use the AF points inside the viewfinder of my Canon 5D Mark IV, the lens will occasionally miss focus and either be front-focused, back-focused, or simply just struggle to find focus as I am taking the shot. This issue is most frustrating when I am doing large group family photos. One contributing factor could be that often these photos are taken in dimly lit churches or reception venues. To work around this issue, I have stopped shooting through the viewfinder and now use the live view on my Canon 5D Mark IV. This way the camera focuses digitally and the AF is 100% accurate. It also allows for face detection which helps me to know exactly who is in focus allowing me to make adjustments as needed.

3. The last factor to note is that the lowest aperture of the Canon EF 17-40mm f/4L USM lens is f/4.  If one were to use it primarily for capturing candids throughout the day, it would require shooting and a higher ISO. In this case, photographers would be better set with a 2.8 zoom lens to allow for shooting at a lower ISO.  For this reason, I use the Canon EF 35mm f/1.4L II USM lens as my main lens for candids so that I have the option of shooting wide open at f/1.4. That said, there are a few rare occasions that I use the Canon EF 17-40mm f/4L USM lens for candid shots such as when the bride is doing a grand reveal of her wedding dress to her bridesmaids and I need a wide angle lens to capture the entire group’s reaction.  In situations like this, the 17-40mm works great as long as there is enough window light!


I always recommend investing in quality lenses, even before upgrading to the latest and greatest camera body.  In just under a decade of owning the Canon EF 17-40mm f/4L USM lens, I have yet to need a repair and have had no reason to replace my copy.  In comparison, in that same time span, I have gone through four different generations of cameras and multiple camera bodies within each generation. This lens has truly stood the test of time and, as I look at switching over to the Canon R system, it will definitely be a lens I adapt to my Canon EOS R5. I will continue to use it for capturing context photos, large group photos, and dance photos. For the price, quality, and the size, it can’t be beat!

For a detailed video review of the Canon EF 17-40mm f/4L USM lens, check out our YouTube review: