Canon 100-400L vs 400 f/5.6L

Written by  Geryl Mortensen

The up-and-coming wildlife photographer who chases birds is also chasing their first 400mm lens whether they know it or not. This quest for more reach often leads new shooters to choose Canon because for years they have outfitted bird and wildlife photographers with the most super telephoto and zoom telephoto options.

When I mentor aspiring shooters I always advocate the importance of a lens roadmap.   My advice regarding glass purchases is to first determine what your main and secondary subjects will be and build your lens roadmap according to your primary and secondary subjects. Update your lens roadmap as your interests evolve.

When bird portraits and or BIF (Bird in Flight) are determined to be a main focus, the aspiring shooter nearly always compares the affordable, handheld, 400mm glass options. In this realm Canon rules the world as they have catered to the wildlife shooter for decades so there is a large inventory of both new and preowned lenses to choose from.

Along the journey the wildlife shooter will usually struggle with a decision between Canon’s 100-400L vs. 400 f/5.6L. Over the years I’ve managed to add both to my quiver and both are certainly handheld favorites with the BIF tribe.  With that in mind I personally don’t know any knowledgeable Canon shooter that had sage mentorship that actually started with just those two lenses as most new shooters are much better served using their glass budget to cover a wider range to start with.

Here’s some food for thought to help you choose between the two. Keep in mind that both lenses technically are considered slow glass, meaning that you need abundant light for best results.  Their fast glass siblings are available but at a serious premium that is often out of reach of the new shooter.

If you need either lens to perform in handheld, low light conditions you’ll likely be disappointed. Not only are they redundant in reach when it comes to wildlife but they’re limited to when you can actually use them in natural light with optimal results. The reason that they’re redundant in reach for wildlife is because you will nearly always be shooting the 100-400 at full reach. You need every bit of 400mm for most bird shots and usually 400mm for most wildlife unless you’re extremely close to a large animal.

Aspiring shooters without actual experience chasing targets at 400mm often have incorrect expectations about how close they have to get to subjects to fill the frame in their dSLR.  For the sake of a familiar comparison, consider that a football is about the size of a mallard duck.  Then consider that the most popular focal length that pro sports shooters use is 400mm to capture head to toe action images of six foot plus football players running with reckless abandon 30 or so yards away. Indeed the football in the running back’s grasp on the cover of SI is a small percentage of the overall frame. This means that the tight cover shots of birds you see in your favorite magazine or posted online are usually aggressively cropped or the shooter was extremely close for the shot either physically or with super telephoto optics.

As a native Texan hosting workshops on our ranch I often cross paths with aspiring bird photographers that grew up with a shotgun in their hand that have now evolved from shooting birds with their Benelli to shooting with their Canon.  These aspiring wildlife shooters usually expect that tracking a bird in flight though the lens at 400mm with their Canon gear will be no more difficult than shooting waterfowl with their Benelli.  The aspiring wildlife photographer is often entirely wrong in their assumptions.

As you learn the craft the 100-400L is easier to acquire targets and get keepers with so I usually recommend it to new shooters over the slightly sharper 400 f/5.6L. You can always sell one and add the other. If you buy preowned or refurbished from Canon and treat your gear with care, there will be little or no disadvantage in doing this as there will be no significant depreciation.

A rule to remember is that quality L glass retains significant value however dSLR bodies do not. This is due to the simple fact that the 100-400L was introduced in 1998 and the model has remained the same for over a decade while dSLR bodies are updated every year or two.

To virtually grasp the experience of tracking birds in flight with each lens without going afield with gear in hand, close one eye and follow a bird or fast moving object with a single open eye.  Not too hard.  This provides a good example of what tracking a bird at 100mm is like before you zoom in with the 100-400L.

Now try again but this time make a dime size circle with your forefinger and thumb and hold over your open eye and follow the bird through the much smaller opening.  No longer child’s play and unfortunately it’s even harder when tracking through the lens.  This is due to the fact that in the virtual example your eye will always keep the target in focus, however when actually tracking a BIF your subject will blur in and out of focus based on how well you keep the focus points/zones on target. Regarding expectations, aspiring shooters do not keep the focus points or zones on target.

The 400 prime is known to have faster AF (auto focus) compared to the 100-400 so it has a slight advantage with both lenses tracking at 400mm but if you pull back the 100-400 the wider field of view makes it much easier to get back on target, even with slightly slower AF.  Again important as you learn the craft, not so much after you gain experience but in the meantime consider that learning should be fun and rewarding.

The 100-400L has 1998 vintage first generation IS (image stabilization) compared to current fourth generation and even Hybrid IS that is now current on new Canon glass. Even so, while the IS on the 100-400 is only marginally effective for pros, it is usually helpful to new shooters. The 400 f/5.6L is sharper, has faster AF, and is lighter, but it lacks the IS feature so it requires a tad more technique to get keepers.

Regarding IS in general; I’ll be the first to tell you that my first piece of L glass in my quiver, and still one of my favorites, was a Canon 80-200 f/2.8L.  It’s true that two decades ago when I purchased it IS was yet to be invented so pros made do with solid technique and fast glass.  The 400 f/5.6L is not considered fast glass, plus 400mm of reach puts you into the realm where IS really does make a big difference when handholding and shooting static objects such as a perched bird.

Image Stabilization (IS) on the 100-400L will help you especially as a new shooter. I know more than a few shooters that can’t get a clean shot with the 400 f/5.6L prime without a monopod or tripod when shooting static objects in marginal light. Keep that in mind when making your decision if you decide to choose one over the other.

Also consider that the 100-400 MFD (Minimum Focus Distance) is 5.9 feet.  The MFD for the 400 f/5.6L is 11.5 feet.  Yes those are feet, not inches. Overall the 100-400 is more versatile but with the MFD so far away you will not be using either to capture any close quarter shots. The 100-400 is a better daytime, outdoors action lens in most cases due to zoom range. It allows you to shoot airshows, motorsports, outdoor soccer, and baseball as a few examples.  Then again versatility is not always better and primes like the 400 f/5.6L are always sharper than zooms like the 100-400L.  Neither lens will perform well when it comes to low light, handheld action shots. If you have a secondary target like children’s sports, the 100-400 may prove to be more versatile.  If wildlife is your only target then you’ll initially be happy with either.  After you master the craft you may find that you prefer the 400 f/5.6L prime.

Handholding a lens and getting a great shot at 400mm is not a simple task. Handholding and tracking a bird in flight compounds the issue. When you manage a great shot it’s like that rare but perfect 300 yard drive on the links; the thrill of the chase resonates with our spirit.

Geryl Mortensen ©2011 – All Rights Reserved

Geryl Mortensen

Birds Afield Co-Founder, Photo Editor, & Writer

Website: www.GerylMortensen.com E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it