This is certainly an interesting lens, if not a new one. Introduced sometime in 2002, at the time of writing, still the only professional-grade DO lens that Canon has brought to market. The DO designation stands for diffractive optics. Canon made use of a multi-layered diffractive optic element in the lens design.
The use of the DO element saves both weight and bulk when compared to conventional lens designs. No longer a new lens, the 400 DO is still current and is still available.
About The Lens
Starting on the outside, the metal body feels and appears to be well-made. The lens is weather-sealed, pretty much to the same degree as any of Canons big L-series fixed telephoto lenses are.
The lens mount is standard Canon EOS, with the rubber weather-sealing ring around the outside. The base of the lens barrel is not textured for extra grip, like many of the latest telephotos from Canon.
At the base of the lens barrel, there is a 52mm filter holder. The lens comes with a clear glass element in the filter holder, and Canon maintain that this should be kept in place when no filter is being used. I never use filters on long telephoto lenses, and make sure to keep this filter holder firmly in place, so that dust stays out.
The 400 DO is supplied with a tripod ring. The ring is of the old Canon design, with a hollow locking knob but it works smoothly and is easy to use. I usually attach a lens plate to the bottom of the tripod mount, for a couple of reasons. The extra length of the lens plate makes it easier for me to hold the lens or rest it when I am shooting handheld. Obviously the lens plate also facilitates quick attachment to a mount. The tripod ring can only be removed by first taking the lens off the camera body.
An aluminium identification plate and a distance scale are located on the top of the lens barrel. There are also mounts for the lens strap that is supplied with the 400 DO. When bigger and heavier lenses are mounted on cameras, it is best to carry the combinations by the lens, rather than having the weight of a big lens hanging on the mount of your camera body. The 400 DO is light enough that it will work both ways.
A switch panel on the left side of the lens barrel houses switches for controlling AF/MF, focus distance and image stabilization. The switches are easy to use, but they protrude slightly from the panel, which means it is quite easy to accidentally bump them onto other settings. This is something to keep an eye on when shooting. Many photographers cover the switches with neoprene lens covers, which makes it much harder to bump them unintentionally. Canon’s newer lenses all have recessed switches that don’t get bumped.
The EF 400 L DO IS also has image stabilization, although in its earlier form, with 2 to 3 stops of effectiveness.
The focus ring is of a normal width, and textured for easy use. I prefer the normal width focus rings over the ultra-wide rings found on Canon’s newest big telephoto lenses, which I find I have to take care not to shift accidentally. In front of the focus ring is a black rubber lens ring that is fixed in place and is home to the lens function buttons, which can be programmed to perform various functions, depending on which camera body you combine with the lens.
The collar where the lens hood mounts is painted white, and it can show scuff marks from contact with the lens hood, although they are not visible when the hood is in place. The hood attaches firmly with the locking knob and provides lots of protection for the front element, due to its depth. There are small screws at the base of the lens hood that can come loose over time. To prevent this happening on my EF 300 f2.8 L IS, which shares the same hood, Raymond from Cameratek applied an adhesive to the threads. That solved the problem. There is a leather-like front cover with a drawstring attachment that fits over the back end of the lens hood when it is turned around on the lens.
Inside the magnesium alloy casing, the EF 400 DO f4 IS houses some high quality optical components. There is one diffractive optic element, and it is positioned just behind the front element, which serves a protective function. The diffractive optic reduces both the size and weight of the lens, when compared to conventional refractive optical elements. Canon claim particularly good chromatic and spherical aberration correction from the diffractive optic lens. There are 17 lens elements in 13 groups. There are 8 aperture blades in the lens diaphragm.
The EF 400 DO f4 IS weighs just 1940g. It is a chunky-looking lens, relatively short, with the large lens hood making it appear bigger than it is. All moving parts are inside the lens barrel, and there is no change in size during focusing. The white paint coating the lens is tough, and also reflects heat when shooting in the sun.
The lens comes in a very robust hard plastic case, that is good for storage, and for travel if space is not an issue…The case is well made and can be locked, but is quite bulky and has no space for anything extra.
The EF 400 DO has also been around for long enough that it is available on the used-gear market.
How Well Does It Work?
One of the things that you instantly notice when you pick up the EF 400 DO f4 IS is that it is lighter than it looks. Despite the large diameter of the front element, the weight of the lens is evenly distributed, making it easy to manage. It is a lens that most people should find ideal for handholding and this is one of the lenses strongest attributes. Of course, handholding any lens with a focal length of 400mm takes some care, and requires good technique. I found the EF 400 DO f4 IS to be a really good lens for wildlife photography
Using the lens on a tripod or mount worked well too, with the tripod collar having a smooth action and a positive locking action. There is a black line painted on the top of the lens barrel that helps with getting the lens and tripod collar properly aligned.
The EF 400 DO lacks some of the added features found on many other big Canon telephoto lenses. There is no Focus Preset ring, or switches for setting in a focus distance to memory. I never use that feature in the field anyhow. There is no power focus option for video. It doesn’t have the ultra-wide focus ring that is found on most of the latest Canon super telephoto lenses. This is not something that I miss, as the new focus rings are so wide that it is easy to shift them inadvertantly when using the new lenses. I like the fact that the EF 400 DO doesn’t have unnecessary ‘fluff’ in its feature set, but has everything that I use and need. Of course those shooters who use some of what I have mentioned here will disagree.
The constant f4 aperture at all focal lengths is a strong point. In low light, f4 is better at gathering light than a lens with a maximum aperture of f5.6, but not as good as one that opens to f2.8. Improvements in low light capabilities of modern sensors may be reducing this advantage somewhat, depending on your own needs.
The lens is equipped with an image stabilizer, and it has two settings. Mode 1 is for regular handholding use, whilst Mode 2 is for tripod shooting or panning, when stabilization is only needed in one plane of movement. The IS system is a little more audible than that on the newest Canon lenses, but not at all intrusive.
The distance limit switch has two settings. If you are photographing subjects at a distance that is not changing too much, setting the switch to suit your working distance can bring benefits to AF speed and reduce AF hunting. Always remember that switch and what your last setting was, as having it on an unsuitable setting can lead to confusion and disappointment. For most of the time, I prefer to keep mine set from the minimum focus distance to infinity. That way, should a subject suddenly appear at a closer than expected distance, I can keep on focusing on i
The minimum focus distance on this lens is 3.5m. This means that there are a lot of other Canon lenses that will be better for photographing very small subjects from close distances. Attaching a 1.4x extender to the lens will help a little with increasing close-up magnification.
I enjoy the 400mm focal length for African wildlife photography a lot. It is long enough that it can get me good portraits of wild animals, especially mammals, complete with blurred backgrounds. It is also just enough for larger or more approachable birds. It gives a good working distance from bigger animals, and enables me to frame well without having to go so close that I disturb the wild subjects. And, if you are moving from an APS-C sensor camera and 300mm lens, the EF 400 DO gives similar framing on a full-frame sensor.
I work with a good number of enthusiast photographers who have chosen the EF 400 DO as their primary long lens for wildlife photography and all of them are big fans of the lens and what it does for them.
Autofocus performance was good with the EF 400 DO f4. The focal length of 400mm is a moderate one in the world of super-telephoto lenses, and the field of view at that focal length is not so narrow that initial pick-up of subjects, especially moving ones, is too difficult with this lens. When paired with the 1Dmk4 or the 5Dmk3, I was able to tackle the fastest of subjects with some confidence.
In the lowest light the EF 400 DO focused a lot slower, but was still accurate. In the field I ended up shooting it paired with my Canon 5Dmk3 long after sunset, and it outperformed the EF 100-400L on a similar body, shooting alongside one another. The 300 and 400mm f2.8 Canon telephotos remain the best options when it comes to focus in the lowest light levels.
Camera Bodies Used
I used the 400 DO on three different Canon dslr’s, each with a different sensor size.
On the Canon 7D with it’s APS-c sized sensor, the field of view is roughly equivalent to 640mm. The lightweight lens combines well with medium-sized camera bodies like the 7D, which is also not too heavy. The pair make for a powerful camera/lens combination with good resolution and AF response. Of course the 400 DO will also work very well with even smaller and lighter camera bodies like the Canon 6D and the Rebel/700D series too. The EF 400 DO/7D combination proved effective for smaller subjects that were far away. Autofocus was good. Low light performance was only average with AF and image quality.
On the now-discontinued Canon 1Dmk4, which has an APS-H sensor in it, and a field of view equivalent to roughly 520mm, I enjoyed great results with subjects of all types and speeds. AF was fast and positive enough for even fast-flying birds, and the 1Dmk4’s resolution, and pixel pitch made this combination ideal for the wide variety of subjects that I typically photograph.
On the 5Dmk3 with its full-frame sensor, the EF 400 DO performed very well. There is not enough vignetting to worry about even on the larger sensored camera, and AF was also fast, and accurate. The EF 400 Do/5Dmk3 combination delivered the best AF and image quality performance in low light of the three.
It is important to define what my own expectations are from these camera and lens combinations in order to better understand my evaluation. All of these cameras and the 400 DO will lock focus on a static or slow-moving subject, in an instant. I don’t even consider that a real test for modern AF systems at all. Instead, most of the shooting that I did with the 400DO involved static and moving subjects, some much faster than others, in bright light and sometimes in very low light.
I always shoot in RAW and process my images in Adobe Camera Raw, which is very similar to Lightroom, and Adobe Photoshop. My evaluation of this lens’ performance with regard to image quality is based upon that workflow.
The EF 400 DO f4 IS USM is a sharp lens, of that I have no doubt. I obtained lots of images that I was very happy with, after an extended period of real-world use with the lens. I actually used the lens for a month of wildlife photography in some of my favourite destinations in the north of Botswana. It is worth noting that I had to choose between my EF 300 L f2.8 IS or the EF 400 DO f4 IS for the trip…airline weight restrictions mean that on that trip, there could only be one big lens. I did some brief testing of the two lenses side by side to make sure that I was happy before leaving my proven 300 f2.8 behind.
I got very good results from the 400 DO, and had no misgivings about using it. Images taken with the 400 DO are not quite as sharp or punchy as those taken with either the older EF 300 f2.8 L IS, or the newest version of that lens. However, they are still quite sharp enough for my needs, and the extra 100mm of focal length came in very handy on many an occasion. Having more pixels on the subject is a good way to maintain high image quality, and having to crop less was a big plus for me in comparison to shooting with the 300 f2.8.
I ended up shooting the lens wide open at its maximum aperture of f4 often, and got very good results. Whilst it may have gotten very slightly sharper when stopped down to f5.6 and 6.3, there was plenty of detail at f4, and I felt confident that I could select my aperture setting with creative intent in mind rather than being forced to stop down for sharpness.
It is been documented that the 400 DO is lacking in contrast, but I did not notice this to any great degree. I shoot in RAW only, and process my keeper images individually anyhow, and almost invariably make contrast adjustments of some sort or another during the processing, regardless of which lens I shot with.
Bokeh was good, though the 300 f2.8 can blur backgrounds just a fraction more.
Colour was well rendered, even in low light. I really didn’t notice any colour fringing and other CA’s in any of the images that I kept. I also did not notice any vignetting with images taken with the 400 DO on the full frame 5Dmk3 sensor or certainly anything that would need fixing in processing.
Shooting against the light the lens provided acceptable results. It can sometimes struggle to focus when a direct light source like the sun is shining into the lens, but in this regard it is about the same as Canons other older series 1 telephoto lenses.
The EF 400 DO can also show a loss of contrast when shooting into bright, direct light but this sometimes be worked around by changing one’s angle or providing extra shade for the front of the lens. The amount of flare that shows up with the 400 DO was not very different to what my EF 300 f2.8 IS L produced. The new generation Canon telephoto lenses are superior by some margin when it comes to dealing with lens flare and direct light contrast loss..
This lens works very well with the EF 1.4x ii or iii extender attached. The combination effectively creates a 560mm f5.6 maximum aperture lens. Autofocus may slow down just a little, and absolute pixel level sharpness may also be slightly affected. In my experience, I get the best results out of lens and extender combinations when pairing them with Canon’s 1D bodies and also the Canon 5Dmk3. The combination worked well enough for me to use it effectively for birds in flight photography.
It is also possible to mount a 2x extender on this lens, and if you are using a 1D series body from the last six years or so, or the 5Dmk3 with its recent firmware upgrade, then you will still have functioning autofocus, although it may be only the centre AF point. I did not try this out myself. I would expect quite a dark viewfinder and it would work best in brighter light.
For a similar price the Canon EF 300 f2.8 L IS ii has a one-stop light gathering advantage and faster autofocus. The EF 400 DO f4 has an extra 100mm of focal length, and it weighs around 400g less. Adding a 1.4III extender to the EF 300 f2.8 L IS ii makes for a 420mm f4 combination, with image quality similar to the bare 400 f4 DO. The weight difference becomes approximately 600g, and the lens plus extender combination is significantly longer and bulkier.
Another option is the Canon EF 400 L f5.6. The EF 400 DO f4 has a one-stop light gathering advantage, faster autofocus, and image stabilization. The EF 400 L f5.6 is 690 g lighter than the EF 400 DO IS, and sells for a fraction of the new price.
The ever-popular Canon 100-400 L f4.5-5.6 IS is lighter than the EF 400 DO IS, has zoom lens flexibility, also has image stabilization and sells for much less. The EF 400 DO has a one-stop light gathering advantage, and faster autofocus.
Canon’s just-released (at time of writing) EF 200-400 x1.4 L IS can do basically everything that the EF 400 DO can do, with the flexibility of a zoom, but it is bigger and heavier, and costs about twice as much.
Light weight and compact size for 400mm focal length
Ease of use
Fast, accurate AF
It may be that my own photographic preferences match up very well with the strengths of the EF 400 DO IS USM, perhaps more so than most. I have a strong liking for the freedom that its light weight and compact size confers when shooting. When you pair that freedom with good image quality, a decently fast f4 aperture and serious focal length, you end up with a strong combination.
The light weight of the EF 400 DO means that it may still be the ideal wildlife lens for those who like to take their pictures whilst they are out walking. It is also perfect for nature photographers that travel a lot by air (and have to deal with airline weight restrictions). In fact, anybody who just enjoys the flexibility that a lens with a decent maximum aperture and focal length in a compact package allows will appreciate the EF 400 DO IS USM.