Canon 100-400 f4.5-5.6L USM/IS Review

Canon 100-400mm Lens Retracted

Over the past two weeks, I’ve had the opportunity to shoot with Canon’s 100-400mm f/4.5-5.6L IS/USM zoom lens. This lens had long been of interest to me because of it’s versatile focal length. However, at a time when I was buying lenses, I shied away from this lens because of rumors that it was not sharp at the 400mm focal length. Also, I was not a fan of the push/pull zoom design.

Canon 100-400mm Lens Extended

Years later, I was still curious about the lens so I took advantage of my Canon Professional Services membership and requested an evaluation copy. So after two weeks of use, here are my thoughts on one of Canon’s most popular professional zoom lenses.


  • Image quality. I was very pleased with the quality of images from this lens. It delivered images that were very sharp and contrasty. I have heard rumors of vignetting at the long end of the focal length on full frame bodies, but I kept the lens mounted on a 1.3x crop factor camera so I can not validate those rumors. On a crop factor camera, I did not notice any vignetting.
  • Extremely versatile and popular focal length. This feature has been something that I have longed for in my current setup. With this versatility, it makes a great sports, landscape, bird, and wildlife lens. You could use it for portraits as well but there are much better options for portraits than this lens. Mounted on a 1.3x or 1.6x crop factor camera body, the focal length increases to 130-520 or 160-640mm, respectively. It’s nice not having to keep switching lenses from shorter to longer focal lengths and back again.
  • Image Stabilization. This is both a pro and con, but more of a pro. I used the lens both on a tripod and hand-held and the IS feature simply worked. It’s first generation IS technology though and I’d love to see the newer improved IS system in this lens. Still, better to have some IS than none at all.
  • Compatible with 1.4x and 2.0x extenders. Although this lens is compatible with extenders, I did not use them nor would I except in very unusual circumstances with this lens due to its variable aperture. Autofocus at f8 would be retained on 1-series camera bodies, but only the center focus point would be active. That’s not a big deal as you can focus and recompose. In a pinch, it’s nice that this lens is compatible with extenders but for my shooting style, if I need more focal length, I’ll use the 500mm lens and mount an extender on that if necessary.
  • Fun. With its very versatile focal range and IS technology, this lens is a joy to walk around with.


  • Autofocus. This feature is actually a pro and a con, but as I’ll explain, it’s more of a con in my experience.  On the pro side, when the conditions are right (e.g. good light, high contrast settings), this lens’ autofocus works superbly and delivers. However, in low-light, low-contrast scenes, the lens is extremely slow and often does not focus at all.  On numerous occasions with a rabbit or bird drinking at a pond, the lens did not lock-on and required a manual adjustment by me to get the lens to lock its focus. Sometimes, I lost the shot while manually adjusting. Anyone who shoots wildlife knows that opportunities come and go and the difference between getting a shot and not getting one can come down to seconds.
  • Push-Pull Design.  I still do not like the design though I did get used to it. The lens has an adjustment ring so you can adjust the tension of the push pull feature. I kept it at the smoothest setting so that I could quickly zoom in and out. The bad thing though is it’s located right next to the manual focus ring and can cause you to accidentally turn the tension ring instead of the focus ring when in manual mode. The push pull design contributes to zoom creep unless you adjust the tension ring to a tighter setting, but doing that makes it harder to zoom in and out.


Anytime you write a camera or lens review the ultimate question people ask is whether or not you would add one to your camera bag. I’m still undecided. If I consider the image quality and zoom versatility, I could easily say “Yes.” However, the autofocus issues are enough for me to answer that question with a resounding “No,” at least for now. This is a lens that I desperately wanted to like and there are many things about it that I do find favorable. However, the last thing I need or want is to depress the autofocus button on my camera and have a lens either hunting to acquire focus or not engaging at all. I can’t afford to risk losing a prized image because the lens did not acquire focus fast enough. Before I completely rule the lens out of my camera bag, I am going to ask Canon for another lens to review. It could be that I had a bad copy and I’d like to test another before I make a final decision. Given this one sample though, would I recommend the lens? Well, if you have demanding expectations about autofocus in low light situations, then I would not. If you can live with its deficiencies, the lens does deliver beautiful images and that focal range is extremely versatile so it still may be worth considering. I’ll have a more definitive answer after I review the second copy so keep an eye out for a future update on this lens.

Until then, may the good light be with you… -Kevin

SAMPLE IMAGES (click on images for a high res review).

Brush Country Sunset. Canon 1D MkII, 100-400/L @ 100mm resting on bean bag on hood of vehicle.

Green Jay. Canon 1DMkII, 100-400/L @ 400mm, f5.6. Gitzo tripod.

Mockinbird. Canon 1D MkII, 100-400/L @ 400mm.

Female Cardinal. Canon 1D MkII, 100-400/L @ 400mm.

Green Jay. Canon 1D MkII, 100-400/L @ 360mm.

Whitetail Doe. Canon 1D MkII, 100-400/L, @ 160mm.

Chachalaca. Canon 1D MkII, 100-400/L @ 300mm. A typical scene in which acquiring autofocus was problematic with this lens.

Canon 1D MkII, 100-400/ L @ 320mm. Setting required a manual adjustment to acquire focus. In this light, the lens should have quickly acquired focus.

Green Jays. Canon 1D MkII, 100-400/L @ 330mm.

Cottontail Rabbit. Canon 1D MkII, 100-400/L @ 340mm. Another example where adjusting focus ring manually was necessary to acquire focus.

Estero LLano Grande State Park

Park Headquarters

The state park at Estero Llano Grande is a 230-acre refuge centrally located in the Rio Grande Valley within the city limits of Weslaco. It is a large wetland environment with numerous lakes, woodlands, and thorn forest. There are many trails and boardwalks that offer excellent morning and afternoon photo opportunities.

View from deck at park headquarters.

Brick Paved Trail. Don't overlook the photo opportunities that abound here. Look for nesting dove, screech owl, butterflies, squirrel and more.

Waders, waterfowl, and shorebirds such as the Green Heron,

Spoonbill Trail and boardwalk leading to Avocet Pond.

Ibis, Roseate Spoonbill, Black-bellied Whistling Ducks, Least Grebe, Black-Necked Stilt, Great Egrets and more frequently visit the park’s waterways. You’ll see different species in summer and winter so it’s a park that you should visit throughout the year. You can also see valley specialties such as the Buff-bellied Hummingbird, Altamira Oriole, Groove-billed Ani, White-tipped Dove, and Chachalaca at the park. Many will be tempted to take a photo while standing on the boardwalk. While there’s nothing wrong with that, to get really impressive images of birds on the various lakes, try shooting from the prone position anywhere along the boardwalks.

Northern Shoveler. Referred to as spoonbills because of the unique shape of their bill, they winter here in the Valley and all along the Southern US Border.

Least Sandpiper. Spends the winter along the Southern US border. It is the smallest shorebird in the world.

Great Egret Backlit By Morning Sun

White-winged Dove & Young In Nest

It may be part of the world birding center network, but there are also reptiles (e.g. snakes, alligators), insects (e.g. butterfly, grasshopper, spider), and mammals (e.g. rabbit, squirrel, bobcat, javelina) to be photographed on the premises. The appropriately named Alligator Lake has several large inhabitants that range from 8 to 12 feet in length and they have had babies so who knows how many alligators live there. The lake is very large so seeing them is no guarantee. I’ve visited the lake about a half dozen times, seen alligators on 3 occasions and only once had one close enough for a good photograph. It’s still worth going to the pond as there is a perch where water birds such as the Neotropic Cormorants can be photographed in beautiful late afternoon light. Along the trail toward Alligator Lake, one can often spot the Common Paraque but you’ll have to keep your eyes open as they are well camouflaged.

American Alligator North of Boardwalk

Neotropic Cormorant at Alligator Lake. Found primarily along Texas Coast, Louisiana, and New Mexico's Rio Grande Valley (yes, they have one too).

Cottontail Rabbit On Trail To Alligator Lake

Common Pauraque. Most active at night, you may have seen these birds if you've ever driven down a ranch road after dark.

Blooming Yucca. Commonly referred to as the Spanish Dagger so be careful around those leaf tips.

CAUTION: The trail along Alligator Lake is close to the water’s edge so stay alert. If pets (should be on leash) or children are accompanying you, keep them close by. There has never been an incident on the trail and the likelihood is really minimal, but it’s always best to err on the side of caution.

EQUIPMENT: Whenever you are after birds, long lens is the key and the longer the better. So at a minimum you’ll want a 500mm lens and it may be best to have it mounted on a crop factor camera. A 400mm may work but when it comes to birds, you can never have enough focal length. Carry your teleconverter with you. Given the diversity of wildlife and habitat, you will have the opportunity to do some wide-angle scenics or even macro work. So what you carry in the field really depends on your photographic objectives, whether that be birds, mammals, insects, landcapes, plant-life or some combination thereof. If you do not have a 500mm lens, you can still capture wonderful images so get out there and get creative. You’ll have a great time.


  • Bobcat exist on the property and have been sighted near the park headquarters and along the brick walkway. Sadly, park rangers report that three were struck by cars on FM 1015 this past Spring.
  • Javelina have been sighted infrequently along Green Jay trail.
  • Look for screech owl in the crevice of trees along the brick walkway and Barn Owl near the feeders in the Tropical Area.
  • Hummingbirds are active by the park headquarters. During migration, look for the Black-chinned and Ruby-throated hummingbirds, along with the native Buff-bellied.
  • If you are visiting the park for the first time, take the electric tram nature tour. It lasts about 45 minutes but you will see the entire park and then you can make your plan of action depending upon your shooting preferences.

I have not taken full advantage of the many photo opportunities at Estero Llano Grande but having done this review, I’ve found a new desire to get back out there to see what I can record. I hope to see some of you there.

Until then, may all your images be tack sharp… – Kevin