10 out of 10 points and recommendedNo loss of IQ, no added CA to 70-200mm f/4 IS Lexpensive, not massive increase in focal length
Works beautifully with the 70-200mm f/4 IS, which is a very sharp lens to start with. I use it routinely for bird watching, using it with the 7D as a telescope to give about 5x magnification, and then blowing up on the screen for study in the hide, adding an extra 40% in linear size and 100% in area. A definite increase in resolution on later printing. The combination of extender and 200mm on the 7D is equivalent to a lightweight f/5.6 448mm 4-stop IS lens on a 5D for field of view.reviewed December 28th, 2011 (purchased for $500)
10 out of 10 points and recommendedGood copies are excellent, marvellous lens for travel and hiking.Bad copies are soft
A re-evaluation after 3 months and more than 1000 bird photos. Initially, I was put off this lens because I had tested a new copy at a local shop, and it was soft. I then tested and bought a good copy. A 2010 used one came up for sale locally and I tested it in parallel with my 400 mm f/5.6 L prime. The zoom was just as sharp as the prime at f/5.6. So, I grabbed it and am delighted. Bird photography most often concentrates on the centre of the image at 400mm. The Canon mtf charts and SLRGear tests show that the 400mm prime and the 100-400mm L are about the same sharpness. The big advantages of the 100-400mm are that for a similar price you get a zoom and two good stops of IS. The guru Art Morris has now given up his favourite toy lens, the 400mm prime, for the zoom. Another advantage is that it slides down to a much smaller length for packing in a camera bag. The 100-400mm is now one of my favourites: I pack it for travel and also for going on hikes. The results are sufficiently sharp that many of my photos are good enough for birdpix.nl, a very picky site. For short walks and sitting in hides, I take my 300mm f/2.8 II with a 2xTC III , which is unbelievably sharp and more reliable precise autofocus.reviewed December 22nd, 2011 (purchased for $1,360)
10 out of 10 points and recommendedSuperbly sharp, relatively light, useful range, superb ISNone
I bought this lens for a safari holiday based on these reviews. They are right - it is a fantastic lens. It is relatively light and well balanced on my 7D and I can walk around all day with the camera in my hand. It is tack sharp at all focal lengths, excellent contrast and colour. The IS is magic - I took a 200mm shot of elephants the other side of a lake lit by headlights at night at 1/6 seconds. I use it for bird photos with sharp crops of the central 600x600 pixels. There is absolutely no degradation in the centre with the 1.4x Mk III extender. It's a wonderful lens, which I use whenever I can. The f/2.8 MkII might be even better, but it is huge and I could not walk around with that all day. I compared it with a 100-400mm for bird watching, and that huge airpump at 400 mm was not quite as good as the 70-200mm at 200mm resized by 2x with Photoshop.reviewed December 23rd, 2011 (purchased for $1,286)
I have posted an album to show the lens with the 1.4x extender outperforms the 100-400mm https://picasaweb.google.com/afersht/Canon100400mmF4556Vs70200mmF4LIS14xExtenderIIIVs400mmF56LLensTest#
9 out of 10 points and recommendedSharp, relatively light, very fast autofocus, reasonable price.Lack of IS
I bought this lens to complement my 70-200mm f/4 L IS for birdwatching. It made me appreciate so much the 4-stop IS on the zoom. The 400mm attached to a Canon has the image wandering all over the place in my shaky hands. At 1/2000s, however, I get superbly sharp shake-free images handheld.reviewed February 24th, 2012 (purchased for $1,050)
Why doesn't Canon make this lens with IS? The IS 400mm lenses are too expensive and are too heavy for hand-held use by us mortals.
The lack of IS is an issue for hand-held use for many shots when the light is low - the level of noise when turning up the iso makes the images unacceptable when cropping just the centre to blow up a distant bird. Because of this, I have now traded the 400mm prime in for a 100-400mm L. It is just as sharp in the centre and has other advantages of a good two-stop IS and packs up small for packing for travel.
The 400mm prime is a good sharp lens, but it can't be scored a 10 when measured against the far more expensive f/2.8 telephotos.
10 out of 10 points and recommendedSuperb IQ, exceptionally good with 1.4 and 2x extenders, hand holdablePrice - but the best is worth it.
I take bird photos with a Canon 7D and either a 100-400mm or a 400mm L f/5.6 lens, hand held, with nice results. But, I wanted something hand holdable that would enable me to keep up with the pros and their longer lenses and tripods. I decided on the 300mm II because it is only 2350 g (less than a lb more than the 400mm f/4 DO) and was reputed to give excellent results with the 2X TC. The results have turned out to be spectacular: the sharpness, contrast and colour are simply unbelievably good, and are hardly lowered by the 2x TC III. Most importantly, the reproducibility of focus is outstanding, which is necessary when you crop 2% of the image and want to see the feathers. Once you have used this lens, it is difficult to go back to the others. And, it is not too heavy for an old guy to carry around all day.reviewed September 1st, 2012 (purchased for $8,500)
10 out of 10 points and recommendedVery sharp at f/4, exceptional focussing and IS. Works very well with Canon 2xTC III.Price
The four earlier reviews sum up well this lens. I use the 300mm f/2.8 II, 100-400mm II, Sigma 150-600mm C and the 400mm DO II on both a 5DIV and 5DS R. Optically at 400mm, there is little to choose among all four of them in the centre, but the 400mm DO II wins out at the edges. The DO II comes into its own in two areas. Firstly, for birds in flight, the exceptionally fast and accurate focussing of the bare lens puts it into a class of its own. Secondly, it works very well with the Canon 2xTC III. It produces contrasty images with great resolution and focusses reasonably fast. If you photographing perched birds and static animals in the open with reasonable light, then is it doesn't make too much difference using the DO II, 100-400mm II and the Sigma C. For birds in flight, the DO is my go to lens followed by the Canon zoom, and in the shade, the f/4 of course.reviewed September 17th, 2017
7 out of 10 points and recommendedGood optics, light and cheapPoor image stabilization. Lack of tripod ring.
I like my Sigma 150-600mm C and really wanted to buy its smaller brother as a light weight for travelling and long hikes, and for my wife to use. I tested carefully four copies from my local dealer. One was a dud. The other 3 were optically excellent, at least as good as my Canon 100-400mm II. But they were all let down by poor image stabilization, and I need good stabilization because I heavily crop bird photographs, often taken at low shutter speeds. The lack of a tripod mount is a serious omission for me as I carry the camera and lens on a strap while hiking and I don't like using a single mounting point on the camera. Focussing is not nearly as fast as the Canon 100-400mm II. So, I'll stick with the Canon as my lightest lens.reviewed September 17th, 2017