When you think of a super telephoto lens, especially one with a wide f/4 aperture, a few words come to mind: big, heavy, and expensive. The Canon EF 400mm f/4 DO IS II USM ($6,899) is smaller than your average 400mm lens, and relatively light, but it certainly isn’t a budget choice. It’s easy to carry all day, and its optical quality is simply impeccable. While it’s pricey, it earns our Editors’ Choice based on its performance. If you can live with a narrower aperture, you can opt for a zoom like the excellent Canon EF 100-400mm f4.5-5.6L IS II USM ($2,199.00 at Adorama) instead, but an f/4 lens adds some versatility, including the ability to take advantage of teleconverter lenses.
When compared with other super telephoto primes, the EF 400mm f/4 DO ($6,899.00 at Amazon) is relatively light at just 4.6 pounds, and small at 9.2 by 5.0 inches (HD). For comparison, the EF 400mm f/2.8L IS II USM ($9,999) tips the scales at 8.5 pounds and measures 13.5 by 6.4 inches, while Canon’s EF 500mm f/4L IS II USM ($8,999) weighs 7 pounds and measures 15.1 by 5.8 inches.
Diffractive optics—the DO in the lens name—are the secret behind the small size and weight. Canon also promises that the DO design works to reduce chromatic and spherical aberration. The lens lives up to that promise, as color fringing did not rear its ugly head in field tests.
Even though it’s not part of Canon’s L series, the 400mm DO is built like an L lens. It features a metal barrel, finished in gray, and is weather resistant so you can use it all types of environments. Front and rear elements are coated in fluorine, which resists drops of water and fingerprints.
A big lens hood is included. It’s reversible for storage. The front element is huge, too big for filters, so a rear drop-in filter system is employed. It supports the same 52mm form factor as other Canon telephoto lenses. The tripod collar is attached to the lens permanently; it rotates and can be locked in any cardinal position.
There are a number of switches on the barrel, including two to control the stabilization system, two to control the autofocus and focus limiter system, and a switch and button combination to lock in a preset focus distance. A series of four buttons at the front of the barrel activate the preset function. If the preset setting is turned off the four buttons pause autofocus operation, without the need to switch to full manual focus mode.
Sports photographers often utilize a preset focus point to quickly lock onto a target at a known location. If you’re shooting an MLB game from a set location, you can record the distance to second base and use the preset buttons to quickly change focus to that plane in order to capture a play, even if you had been photographing the first baseman or pitcher only moments before.
The minimum focus distance is 10.8 feet (3.3 meters). With a lens of this focal length you’re not going to get too close to subjects, or else you’d enter macro territory. If that’s what you’re after, the EF 100-400mm does a better job with close focus—it locks onto subjects at 3.2 feet for a 1:3 magnification ratio. Another telezoom option, the Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary ($870.00 at Amazon) , has an even narrower f-stop, and focuses to 9 feet for a 1:5 magnification ratio.
One of the reasons to choose a prime over a zoom is the aperture. At f/4 you’ll be able to shoot in more challenging light while keeping your shutter speed short and not pushing your camera’s ISO as far as you would with an f/5.6 or f/6.3 zoom.
Another is teleconverter compatibility. You can add a 1.4x or 2x teleconverter and extend the reach of the lens to 600mm or 800mm. With a 1.4x you’ll retain full autofocus compatibility with most Canon bodies; but you’ll be limited to high-end models with support for focus at f/8. One of those is the APS-C EOS 7D Mark II ($1,499.00 at Dell) —when paired with the 7D Mark II and coupled with a 2x teleconverter, the 400mm lens captures a field of view similar to a 1,280mm lens mounted to a full-frame body.
I tested the 400mm DO with the 50MP Canon EOS 5DS R ($3,899.00 at Buydig) . At f/4 the lens scores a strong 3,576 lines per picture height on a center-weighted sharpness test. That’s much better than the 2,200 lines we want to see at a minimum from a high-resolution body like the 5DS, and better yet the lens delivers image quality that’s just as strong at the edge of the frame as it is in the center.
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Stopping down to f/5.6 improves the score to 3,909 lines. There is a slight drop at narrower apertures, starting at f/8 (3,719 lines) and f/11 (3,267 lines), but it’s not significant until you stop down further. At f/16 the score drops to 2,996 lines, and it continues to fall at f/22 (2,485 lines) and f/32 (1,588 lines).
Distortion is a complete nonissue. The lens reproduces straight lines without any sort of inward or outward curve. I also tested the lens for uniformity of illumination. At f/4 the corners of the frame are dimmer than the center by about 1.2 stops (-1.2EV), which is just outside our -1EV threshold of acceptability. At f/5.6 the deficit is cut to -0.8EV, and it’s absolutely marginal at narrower apertures.
The Canon EF 400mm f/4 DO IS II USM is simply a phenomenal lens. It delivers excellent edge-to-edge sharpness, even at f/4, with uniform illumination and no distortion. And, despite a super telephoto focal length and wide aperture, it is amazingly light and compact. It’s expensive, but not out of line when compared with similar lenses. Based on its performance and form factor, it’s an easy pick as Editors’ Choice. Some photographers may prefer a less expensive alternative. Zooms like the Sigma 150-600mm Contemporary and Canon 100-400mm don’t capture as much light at any focal length, but cost a lot less.