Canon EF 400mm f/4 DO IS USM Lens Review

The Canon EF 400mm f/4 DO IS USM Lens is Canon's first DO (Diffractive Optics) lens - yielding 400mm f/4 IS performance in a relatively small and light handholdable package.

Small and light are of course relative. Someone used to shooting with a Canon EF 28-135mm IS Lens will regard the 400 DO as being large and heavy. But, to someone used to shooting with a Canon EF 300mm f/2.8L IS Lens, the 400 DO will feel light (4.3 lb vs. 5.6 lb / 1,940g vs. 2,550g) and definitely more easily handholdable. I really like the weight of this lens. The difference between it and the 300 f/2.8 feels even bigger than the 1.3 lb (610g) spec difference indicates.

Pictured above from left to right are the Canon EF 400mm f/4L DO IS USM Lens, Canon EF 300mm f/2.8L IS USM Lens and Canon EF 500mm f/4 IS L USM Lens with optional Wimberley Lens Plates attached. Wimberley recommends the relatively small P20 model for the 400 DO.

Combining a light and relatively fast lens with IS (Image Stabilization) makes handholding even more possible. The 400 DO's tripod sensitive IS enables handheld shots at about 2 f-stops slower than a non-IS 400mm lens. Remember - IS will not stop subject motion. Both Mode 1 and 2 IS are available. Mode 1 IS attempts to stop camera/lens motion in all directions. Mode 2 IS allows panning with a moving subject while stabilizing camera motion in one axis. As with all IS-equipped lenses, an on/off switch allows IS to be disabled.

Pictured above from left to right are the Canon EF 400mm f/4L DO IS USM Lens, Canon EF 300mm f/2.8L IS USM Lens and Canon EF 500mm f/4 IS L USM Lens with their respective lens hoods attached.

Utilizing Ring USM (Ultrasonic Motor), the Canon EF 400mm f/4 DO IS USM Lens focuses fast, quietly and accurately. FTM (Full Time Manual) focusing is enabled. A 2-position focus limiter switch allows focusing distances to be limited to a minimum of 3.5m or 8m. Limiting the focus distance range can improve focus lock times and reduce hunting. Autofocus Stop buttons (round black buttons on the black ring) near the objective lens allow autofocus to be temporarily stopped.

The apparent sharpness of this lens is not in direct relation to its price. The Canon EF 400mm f/4 DO IS USM Lens is reasonably sharp at f/4 and sharp when stopped down to f/5.6. But it is not as sharp as the Canon EF 300mm f/2.8L IS Lens (few lenses are). The 300mm f/2.8L IS with a Canon 1.4x Extender attached (yielding a heavier but less expensive 420mm f/4 IS lens) is similar to the 400 in sharpness. The Canon EF 500mm f/4 IS L Lens is sharper as well (similarly priced but nearly twice as heavy). The much smaller, lighter, slower (max aperture) and far less expensive Canon EF 400mm f/5.6L Lens and Canon EF 100-400mm f/4.5-5.6L IS Lens compete well with the DO in sharpness at f/5.6 and are even sharper in the corners (and one of them is a zoom).

Contrast is the Canon EF 400mm f/4 DO IS USM lens's optical shortcoming - which also hurts the apparent sharpness performance. I found that most of my shots needed a healthy contrast boost in post-processing (or a positive in-camera contrast setting). I could easily tell which image was taken with the 400 DO when looking at comparative shots on a monitor. The 300 f/2.8 IS has much better contrast than the 400 DO. Even the Canon 100-400mm L has better contrast when the vignetting in the full frame corners at 400mm does not get in the way. Low contrast is my most-significant disapointment with the 400 DO - fortunately it is something that post-processing can help.

Light fall-off is minor and distortion is negligible.

Pictured above is the 400 DO and the Canon EF 100-400mm f/4.5-5.6L IS Lens extended to 400mm. Notice that the biggest difference is in hood size.

The Canon EF 400mm f/4 DO IS USM Lens has been criticized for its poor specular highlight bokeh (OOF blur quality), but I have seldom encountered this problem. Specular highlights can have a target-appearance at worst - concentric circles instead of a smooth blur. I can't say I like the bokeh of this lens more than Canon's other 400mm Lenses, but the 400mm focal length combined with a relatively wide aperture can nicely separate a subject from its background.

Model	Dimensions w/o Hood		Weight		MFD		MM
Canon EF 200mm f/2L IS USM Lens	5.0 x 8.2	(128 x 208)	5.6 lbs.	(2,520)	6.2'	(1.9m)	.12x
Canon EF 300mm f/2.8L IS USM Lens	5.0 x 9.9	(128 x 252)	5.6 lbs.	(2,550)	8.2'	(2.5m)	.13x
Canon EF 400mm f/2.8L IS USM Lens	6.4 x 13.7	(163 x 349)	11.8 lbs.	(5,370)	9.8'	(3.0m)	.15x
Canon EF 400mm f/4 DO IS USM Lens	5.0 x 9.2	(128 x 233)	4.3 lbs.	(1,940)	11.5'	(3.5m)	.12x
Canon EF 500mm f/4L IS USM Lens	5.8 x 15.2	(146 x 387)	8.5 lbs.	(3,870)	14.8'	(4.5m)	.12x
Canon EF 600mm f/4L IS USM Lens	6.6 x 18.0	(168 x 456)	11.8 lbs.	(5,360)	18.0'	(5.5m)	.12x
Canon EF 800mm f/5.6L IS USM Lens	6.4 x 18.1	(162 x 461)	9.9 lbs.	(4,500)	19.7'	(6.0m)	.14x

The relatively long minimum focus distance of 11.48' (3.5m) gives the 400 DO a low maximum magnification (relative size of subject on sensor at the closest focus distance) value of .12x. This is not dissimilar to most of Canon's other super telephoto lenses but much lower than the 100-400's .2x value. Adding 12mm and 25mm extension tubes improves maximum magnification slightly to .16x and .20x respectively

The 400 DO is compatible with the Canon Extender EF 1.4x and Canon Extender EF 2x. The resulting magnification capability with the extenders is .17x and .24x respectively.

Load Comparison Images

Physically, the Canon EF 400mm f/4 DO IS USM Lens is loaded. Build quality is excellent. Construction is dust and weather-resistant. One of the few features missing is the focus preset feature (I seldom use this anyway) found on many of the other Super Telephoto lenses.

I found my first 400 DO's included lens hood aggravating. Not the hood itself, but the fit of the hood. It was extremely tight - too tight to get on/off - unless you gently wiggle and tilt the hood just right (objective end of hood tilted toward the hood's thumbscrew and wiggled side to side - and not toward or away from the tripod ring foot) during the install/removal. Get the gentle wiggle and tilt just right and the hood removes or installs easily. I tried the lens hood from my 300 f/2.8 IS (they share the same Canon ET-120 hoods and leatherette lens cap) to confirm that the hood itself was not the problem. My second 400 DO's hood fit tight, but better. And the hood on my third 400 DO fits fine.

Pictured above is the leather-like lens cap shared by this lens and the Canon EF 300mm f/2.8L IS USM Lens. This cap features a rigid lens cap with a flexible hood cover. All of Canons large Super Telephoto lenses come with a similar cap.

The Canon EF 400mm f/4 DO IS USM Lens comes packed in a protective and lockable Canon 400B lens hard case. The 400B lens case is identical in outside dimensions to the 300 f/2.8's case: about 14.5"W x 9.5"H x 10"D (33.94mm x 22.23mm x 23.4mm). When you open a Canon Super Telephoto Lens case, you are greeted with a smell that is right up there with new car smell (in my opinion of course). Not so with the 400 DO. It does not smell bad, but not like the rest of the Super Telephoto cases I've opened. I'll leave this explanation for someone else. A neck strap that attaches directly to the lens is included.

The 400 DO utilizes 52mm drop-in filters and comes equipped with a drop-in gel filter holder with a glass filter installed. This glass filter is also a nice way to catch dust before it drops deep inside the lens. The Canon 52mm Drop-In Circular Polarizer Filter is probably the most-used drop-in filter available for this lens.

My first 400 DO was purchased retail/new in April 2005, the second new lens had a Canon lens date code of Aug 2005 and the third indicated July 2005. There has been some talk about much earlier production models having lower optical quality. I have not tried one of the earlier models and verify this rumor, but Canon Inc. has confirmed (to Chuck Westfall, Canon USA) that, as of May 6, 2008, there have been no changes made to this lens since Canon started selling it.

If the natively lower contrast is not an issue for you, the Canon EF 400mm f/4 DO IS USM Lens makes an excellent sports lens. The long 400mm focal length will bring sports action up close. A relatively fast f/4 aperture will stop action in lower light levels and nicely blur the background.

The Canon EF 400mm f/4 DO IS USM Lens also makes an excellent walkaround wildlife lens. IS helps get the handheld shots in the lower light levels that wildlife tends to be active in and the diffractive optics keep the weight low.

If you don't mind some extra weight and a shorter focal length (unless you add a 1.4x extender), the Canon EF 300mm f/2.8L II IS Lens performs significantly better. The Canon EF 400mm f/5.6L Lens and Canon EF 100-400mm f/4.5-5.6L IS Lens are other good options - though definitely not as exciting to look at and use.