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Canon EF 100-400mm f/4.5-5.6L IS USM is the longest telephoto zoom lens currently manufactured by Canon. First released back in late 1998, the lens currently retails around US$1,600 (as of October 2010) and is typically used for wild-life and sports photography. On APS-C type cameras the field of view of this lens resembles that of a 160-640mm lens on a full-frame camera.

The lens construction consists of 17 elements in 14 groups, including one S-UD (Super Ultra-Low Dispersion) and one CaF2 (fluorite) glass elements. The lens has linear extension type zooming mechanism, meaning you actually need to pull/push the front side of the lens to zoom. Not surprisingly, the lens, which looks bulky and heavy, becomes quite a monstrosity once extended to the full zoom. It weights 1,380g (3.1lb) and measures 92x189mm (3.6x7.4in) when fully collapsed. The minimum focusing distance is 1.8m with maximum magnification of 1:5 at 400mm. The front element of the lens does not rotate during zooming so you can use a polarizing filter (without hood at least). The lens accepts 77mm filters.




The build quality of the lens is superb as expected from an L lens – the barrel is solidly built and shows no wobbling, with smooth rubberized focus ring. The lens sports a ring-type USM drive which results in a fast and silent auto-focus. To help avoid unnecessary hunting and accelerate AF, you can switch focus limiter between 1.8m to infinity and 6.7m to infinity modes. Full-time manual focusing is also supported. The lens also offers first generation Image Stabilization technology which helps you gain an equivalent of two f-stops when handholding the camera. The IS supports two modes – mode 1 for correcting motion in both vertical and horizontal axis and mode 2 for correction motion in vertical axis only. The first mode is intended to assist in taking pictures of static scenes, whereby the second mode will help when tracking moving target.

The lens is compatible with Canon’s extenders 1.4x II and 2x II and is compatible with Canon’s Gelatin Filter Adapter IV. The factory box includes the Canon EF 100-400mm f/4.5-5.6L IS USM lens, front and rear caps, ET-83C lens hood, Tripod Mount Ring B, Lens Case LZ1324, manual and warranty card.


Lens Composition 17 elements in 14 groups
Angular Field 24 - 6 degrees
Minimum Focus 1.8m/5.9ft
Focusing Action AF/MF, USM
f-stop Scale f/4.5-f/32, camera-controlled
Filter Size 77mm
Lens Hood ET-83C (included)
Weight 1380g/3.1lb
Dimensions 92x189mm/3.6x7.4"
Lens Case LZ1324 (included)



Canon EF 100-400mm f/4.5-5.6L IS USM is one of the more controversial lenses out there that often get a lot of heated arguments on online forums. Some people love the lens, others seem to hate it. My first review of this lens generated quite a wave of emails and online comments, which just proved to me how polarizing the issue of lens testing could be. Since the first review, I had the opportunity to test 3 more samples of this lens. The second sample, lent to me by a friend, did not produce results any different from the original one used in the review. Third sample, purchased on eBay turned out to be a lemon, suffering from misalignment, and finally the fourth sample, purchased new from B&H turned out to be the best (in terms of resolution) out of the four. The review you are reading is based on this fourth sample, which has a date code UY, indicating that it was manufactured in 2010 (the previous three samples were manufactured in 1999, 2002 and 2003 respectively).

The concept of an affordable, long telephoto zoom, is absolutely right, no matter from which angle you are looking at it. Canon's 100-400mm f/4.5-5.6L IS USM tries to bridge the gap between the stellar 70-200mm series of lenses and super long (super expensive and super famous) telephoto fixed focals like EF 300mm f/2.8L IS USM and EF 400mm f/2.8L IS USM. Needless to say, that EF 100-400mm f/4.5-5.6L IS USM has a very big shoe to fill, when we put it into such an outstanding company of lenses. But realistically speaking, we should remember that this lens is all about compromises. First of all, to keep the price (as well as the weight) down, Canon had to make some sacrifices, including making the lens fairly slow. Personally, I don't have a major problem with slower lenses, given that most modern SLRs now have fairly good ISO rates over 1,600. However, I do think that the designers erred on the zoom range here - the 100-200mm range with maximum supported aperture of f/4.5-f/5 (respectively) is not particularly attractive given the excellent selection of 70-200mm zooms that Canon offers. Instead of adding extra 100mm on the wider range, I would have preferred a 200-400mm range but with a constant maximum aperture, like Nikon's famous AF-S VR Nikkor 200-400mm f/4G (and at a cheaper price obviously). Now, even with the latest price increases (the price of EF 100-400mm f/4.5-5.6L IS USM jumped from ~$1,400 in 2007 to ~$1,600 in 2010), this is still one of the cheapest lenses in its class. The only other super tele zoom that comes to mind here is Sigma's 50-500mm f/4.5-6.3 APO DG OS HSM lens. Nikon's venerable 200-400mm zoom is about 4x more expensive, so while I can't call a lens costing ~$1,600 cheap, in relative terms it is actually priced fairly aggressively.

From ergonomics perspective, EF 100-400mm f/4.5-5.6L IS USM is not your typical zoom - combination of the push/pull zooming mechanism and chunkiness may make handling (particularly hand-holding) of the lens somewhat difficult. While the lens is no heavy-weight in absolute terms (compare its 1,380g against EF 300mm f/2.8L IS USM and its 2,550g for exampel), the combination of the lens and a larger SLR body like 1DsMkIII do make the package rather heavy (not heavy enough to warrant a Gimball head though - a better ballhead like ArcaSwinn B1, Kirk BH-1 and even lightweight Markins Q3 have no issues locking the package securely and without any.shifts). Granted, there are always users who claim that they can hand-hold a 10kg combo and still get excellent results at slow shutter speeds, but I am not one of them - when hand-holding the lens and shooting at its longest zoom point, my keep ration was only ~30% with shutter speeds below 1/500 (I am talking here about the keep ratio solely because of the motion blur). With IS on, the keep ratio went up to ~50%, but to get it to the desired 80-90%, I just had to go with faster shutter speeds - 1/800 would typically do the trick for me.

The whole push/pull zooming mechanism of Canon EF 100-400mm f/4.5-5.6L IS USM has seen a fair amount of heated debates, with some arguing that the mechanism is not as good as traditional (rotational) zoom mechanism because it is slower, less accurate, pulls in dust into the camera, etc. Others are arguing that this is the best mechanism for a long telephoto. Whether you like it or not, you will have to live with it if you plan on using this lens - my personal take on this is that while I indeed prefer traditional zooming, I do strongly believe that given time and practice anyone can get used to and be fairly efficient with the push/pull process on this lens. And with regards to the often cited claims that the lens will be pulling a lot of dust into the camera, you should realize that most of us end up with more dust in the camera because of frequent lens changes, not because of the occasional particle that EF 100-400mm f/4.5-5.6L IS USM might suck in. Unless, of course, you're shooting in a really dusty or sandy environment, like a desert on a windy day, but that's a different story.

Continuing with the push/pull zooming for a little bit longer, I wanted to mention the biggest annoyance for me was the inability to zoom in with one hand. To zoom, you need to first loosen a dedicated tension ring, which prevents the lens from collapsing or extending on its own. You can't really grab the ring with your index finger and thumb, while grasping the lens barrel with the remaining three fingers - the tension ring is actually coupled with focusing ring and rotates with it freely. You need to actually hold the focusing ring, while rotating the tension ring, which is basically impossible to do all at the same time while maintaining focusing on the subject. Your best bet is probably not to tighten the tension ring at all and keep the lens from sliding with your hand. of course when pointing the lens up or down, that process can get tedious as well. As I said, you just need to get used to it...

Like most modern Canon lenses, EF 100-400mm f/4.5-5.6L IS USM designers assumed that the lens will be used predominantly in auto-focusing mode - manual focusing is possible with the dedicated zoom ring, but with the rotational thrust of ~60 degrees, it does not offer that much precision. The good news, however, is that the AF speed on this lens is fairly decent, particularly if you limit the AF distance using the AF limiter. AF is fairly accurate under normal lighting conditions and is the case with the virtual majority of cameras using contrast-based focus detection, it hunts to some degree in low light and low contrast conditions.