The Canon EF 100-400/4.5-5.6L IS USM is Canon's premium telephoto zoom lens. It competes with the EF 300/4L IS and the EF400/5.6L prime lenses as a telephoto and with the EF 70-300/4-5.6IS as a wide range telephoto zoom. In this series of tests I shot with the EF100-400/4.5-5.6L IS alongside the EF300/4L (non-IS version) and the EF 70-300/4-5.6IS.
The EF 100-400IS is comparable in size to the EF 300/4L. It's a little shorter when zoomed 100mm and quite a bit longer at 400mm (as can be seen in the image above). The EF 70-300IS is smaller and lighter than either of the other two lenses.
|Lens||Diameter||Length (wide)||Length (tele)||Weight||Approx Cost|
|EF 100-400L IS||3.6"||7.4"||10.75"||1363g||$1425|
|EF 70-300L IS||3"||5.6"||8.1"||630g||$555|
|EF 300/4L||3.5"||8.4"||8.4"||1161g||~ $800 (used)|
|EF 300/4L IS||3.5"||8.7"||8.7"||1190g||$1210|
The maximum aperture of the EF 100-400/4.5-5.6L IS varies with focal length as shown in the table below. Note that at 300mm the maximum aperture is f5.6, so it's a full stop slower than the EF 300/4L.
|EF 100-400/4.5-5.6L IS||-||f4.5||f5.0||f5.6||f5.6||f8|
The EF 100-400/4.5-5.6L IS USM is unusual in the current Canon lens lineup in that it's the only zoom with a "push-pull" action rather than the normal "Twist to Zoom" found on all other current Canon zooms. Whether you like push-pull zooms is a personal preference. Some people do, some people don't. I found it a little unusual at first, but after working with the lens for a while I didn't find it awkward. The zoom action has a locking ring which can be used to adjust the amount of effort needed to zoom or can be used to lock the zoom at a particular setting. There have been a few comments on the web that the push-pull action (which changes the internal volume of the lens) tends to suck air in and out and so may bring in dust particles which can find their way onto the elements (and maybe even onto the camera sensor). I didn't have the lens for long enough to tell whether or not that's true, but there are thousands of these lenses being used every day and I really don't see too many complaints.
The IS system has two modes, a dual axis mode which stabilizes both horizontal and vertical motion, and a single axis mode which switches off stabilization of the axis of motion if the lens detects that you are panning the lens. There's also a focus range limiter to make focus acquisition faster if you know your subject will be more than 6m away. Focus is, of course, fast and silent since the 100-400IS uses a ring USM motor.
The lens is supplied with a hood, which is quite large and when mounted makes the lens fairly impressive, especially when zoomed out to 400mm. Not a lens for covert photography! Since it is a fairly large and heavy lens, it has a rotating tripod mount attached which should be used when the lens is mounted on a tripod. However it's light enough to be handheld fairly easily (it weighs just over 3lbs)
Of course what counts most isn't size, weight or cost, it's how well the lens performs and whether it's worth its price. To determine how well the 100-400IS performed I took a series of shots of a resolution target, as well as several series of shots of "real world" subjects. I took similar shots (when possible) using the EF 70-300IS and 300/4L so that I could compare performance. On this page I'll briefly summarize the results of the tests. For more details and samples from the images, see the EF 100-400/4-5.6L IS USM Test Images page. All the test shots were made using a Canon EOS 40D, an APS-C sensor DSLR. All three of the lenses I looked at have full frame coverage of course and performance at the edges and corners of the image would be expected to be better for APS-C images than full frame images.
At the edges of the image the differences were somewhat more easily visible. The 70-300IS showed somewhat lower contrast and sharpness than the 100-400IS and both lenses benefited from being stopped down to f8. The 300/4L prime lens was sharp to the edge of the image, even wide-open at f4. This is the advantage of a prime lens of course.
The performance of the 70-300IS + Tamron 1.4x was the worst, showing softening of the image in the center of the frame and significant softening and lowered contrast at the edges, even when stopped down a stop. Since this combination starts out at f8, when stopped down a stop it becomes f11. It's also manual focus.
The 100-400IS and 300/4L showed higher image quality both in the center of the frame and at the edge. The images from these two lenses were very similar, both wide open (f5.6) and stopped down a stop (f8). Both were better at f8 than at f5.6.
The difference between the 1.4x and 2x TCs shows up here. Wide open (f8) the 100-400IS + 1.4x TC gave the better image. In the center of the frame, the image from the 300/4L + 2x showed lower contrast and so appeared less sharp. Stopping down improved the 300+2x combination more than the 100-400+1.4x, but the zoom maintained its slight advantage at all aperture. Of course the focal length was a little shorter too (560mm vs. 600mm). Both lenses showed quite similar visible chromatic aberration at the edges of the image.
The same trend was seen at the edge of the frame. Both lenses held up well, but the 100-400IS gave images with slightly higher contrast and sharpness at all apertures.
See the EF 100-400/4-5.6L IS USM Test Images page for examples.
About 10 years ago I looked at an EF 100-400/4.5-5.6L IS and I wasn't too impressed. It was good, but it wasn't as good as a 300/4L. Since many users had reported very good results with their 100-400IS lenses I thought I should give it another chance. Well, I can say that the 100-400L I tested here was very good. Image quality is pretty close to that of the EF 300/4L, except perhaps at the edges of the frame at 300mm, where you might well expect a prime lens to do better. With a Canon 1.4x TC it slightly outperformed the EF300/4L with a 2x TC, though at a slightly shorter focal length (560mm vs. 600mm).
So which of the three lenses (100-400IS, 70-300IS, 300/4) is best? As usual, it depends what you are looking for.
The EF 70-300/4-5.6IS USM is the smallest, lightest and cheapest of the three lenses, and hold up pretty well all the way to 300mm in the center of the frame (though edge quality starts to drop off a little at 300mm). For the price it's certainly good value, but it doesn't have much potential past 300mm. It's OK with a Tamron 1.4x TC, but I wouldn't recommend using a 2x TC on it.
The EF300/4L USM is very sharp from center to edge, even wide open at 300mm. It also has a 1 stop advantage over the 100-400IS at 300mm (f4 vs. f5.6), which could be important if you are shooting sports of action, or if you want to isolate a subject via minimum DOF. With a Canon 1.4x it's about equal with the 100-400IS, though of course getting from 300mm to 420mm takes a lot longer than simply zooming there! With a 2x it can give decent image quality, but it's best stopped down a stop, which makes it a 600mm f11, so you need good light. It's a reasonable assumption that the current EF 300/4L IS will perform similarly, at least that's what I found when I tested IS and non-IS versions side by side some years ago.
The EF 100-400/4.5-5.6L IS USM is clearly the winner when it comes to a combination of quality and convenience. The ability to zoom out to 400mm makes it much more useful for situations where action can be close or far away, for example in sports photography. In such situations taking the time to add a TC to a prime lens can mean you miss critical action. It is a stop slower than the 300/4L at 300mm, and that may be it's only major drawback when comparing the lenses. The prime lens allows the use of faster shutter speeds. Of course the 100-400IS a little more expensive and a little heavier, but that's only to be expected in a zoom. With a 1.4x TC it produces quite good image quality, though unless you play tricks by masking off pins, it won't AF on most EOS bodies. Even with a 2x TC the image is usable, though manually focusing at f11 isn't particularly easy and the lens really need to be stopped down a stop (to f16) for better image quality.
What about the 70-200/2.8L IS USM and 1.4x and 2x TCs? Well, I didn't do a direct comparison, but I did test that lens combination against the 300/4L a few months ago [see EF 70-200/2.8L IS USM review] and found that it wasn't as sharp as the 300/4L or 300/4L + 1.4x. So I'd conclude it wouldn't be as good at 280mm and 400mm as the 100-400IS lens is. It would probably be better (and quite a lot faster) at 100 and 200mm of course.
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