Canon EF 300mm f/2.8L IS USM

(From Canon lens literature) Telephoto lens newly equipped with an Image Stabilizer enabling hand-held shooting for easier movement. The fluorite element and two UD-glass elements effectively correct the chromatic aberrations prone to occur with telephoto lenses.

SLRgear Review
May 19, 2008
by Andrew Alexander

Released in 1999, the Canon 300mm ƒ/2.8L is one of Canon's group of fast image-stabilized long primes. This group includes the 200mm ƒ/2, 300mm ƒ/2.8, 400mm ƒ/2.8, 500mm ƒ/4 and 600mm ƒ/4 IS lenses. As an L-class lens, the 300mm ƒ/2.8 is constructed with a fit and finish which makes one appreciate its $4,000+ price tag.

On a Canon sub-frame sensor body, the lens will have an effective field of view of 480mm (300mm x 1.6).

Sharpness
The Canon 300mm ƒ/2.8 is one of the sharpest lenses we've ever tested. This is a lens designed to be used wide open at ƒ/2.8, and it shows in the test results. On a subframe 20D at ƒ/2.8, the far right edge of the frame barely reaches 1.5 blur units, and the rest of the frame edges just above 1 blur unit. This performance improves (as if it had much room to improve) by ƒ/4, where it is essentially tack-sharp across the frame. It's just as sharp through ƒ/5.6-8, and by ƒ/11 we begin to see the effects of diffraction limiting, though at this level to say that the sharpness is degrading needs some qualification. Sharpness hits 1.5 blur units at ƒ/11, and 2 units by ƒ/16. It's possible to shoot at ƒ/32, but here you actually encounter some legitimate softness issues at 5 blur units across the frame. This really isn't a lens you're going to be shooting at ƒ/32, though.

Performance on a full-frame 5D is equally impressive. The lens is really challenged by the full-frame sensor, with 1.5 blur units in the central region and just shy of 2 blur units in the corners at ƒ/2.8. This kind of performance is the norm through to ƒ/11, not getting any better or worse; at ƒ/11 things even out somewhat and you get a consistent 1.5 blur units across the frame. It never hits the ''tack-sharp'' results we saw on the sub-frame 20D, but the results are still excellent. By ƒ/16 diffraction limiting sets in, with sharpness showing up at 2 blur units across the frame, and the lens produces fairly soft images at ƒ/22-32 (2.5 and 4 blur units respectively).

The 300mm ƒ/2.8 is a lens which really takes advantage of the reduced-frame sensor on the 20D, where the sensor is using only the sweet spot of the glass. On the 20D the lens produces some amazingly sharp results when used in the larger range of its aperture selection. It's impressive on the 5D as well; I think it would be overly critical to say that the corners have issues with sharpness when reaching 1.5-2 blur units. It's not tack-sharp across the frame, but for such a long focal range, it is very impressive performance.

Chromatic Aberration
Canon has taken the reduction of chromatic aberration seriously in this class of lens, by employing a fluorite element for the highest optical quality. As further proof that the lens is optimized for shooting at large apertures, our test results for chromatic aberration show that CA is really only an issue when you stop the aperture down to ƒ/16 or greater. At that range you encounter some CA in the corners, around 6/100ths of a percent of frame height. Generally though, CA is not a problem for this lens and the sample images seem to bear this out.

On the full-frame 5D, CA is even less of a problem owing to the larger pixels of the full-frame sensor. CA still increases as the aperture is stopped down, but in this case, CA doesn't exceed 3/100ths of a percent of frame height, even at ƒ/32.

Shading (''Vignetting'')
The 300mm ƒ/2.8 has a touch of corner shading when set to ƒ/2.8 on a sub-frame sensor body, but one shouldn't get overly anxious over an image that's a quarter-stop darker in the corners than in the center. By ƒ/4, there's no light falloff to speak of.

On a full-frame body however, corner shading becomes a bit more problematic. Set to ƒ/2.8, the lens produces an image that is 3/4 of a stop darker in the corners than the center, which is relatively noticeable, especially in our sample images. By ƒ/4 this shading drops to a quarter-stop, and at ƒ/5.6 and greater corner shading is negligible.

Distortion
The 300mm ƒ/2.8 shows almost no distortion on a subframe sensor body, at least, none to get worried about: we're talking less than -0.1 pincushion distortion. On a full-frame body, this performance is essentially the same: -1.5% pincushion distortion.

Autofocus Operation
The 300mm ƒ/2.8 focuses extremely fast, and also very quietly. As a USM lens, you can override focus results at any time by just turning the focus ring. The lens is also equipped with a focus preset system, which allows the lens to ''memorize'' a given focus distance, and return to that focus distance when the dedicated present ring is tapped. Finally, the lens is equipped with a focus limiter switch, enabling the focus performance to be improved by limiting the range of distance being focused upon. Focus limiting options are 2.5m to 6.4m, 6.4m to infinity, and 2.5m to infinity.

Macro
With a maximum magnification of 0.13x and a minimum close-focus distance of 2.5 meters (8', 2'') there are better choices for macro work.

Build Quality and Handling
Strap yourselves in, there's a lot to talk about with this lens.

The 300mm ƒ/2.8L IS epitomizes the saying of something being ''built like a tank''. Like all L-series glass, the 300mm is dust- and weather-resistant, built with great attention to detail. The lens ships in a hard case with a protective interior, and given the price of this lens, it is indeed a welcome part of the kit. In addition, there's no front cap for this lens - rather, there is a leather-like lens hood to protect the whole front half of the lens.

The lens offers a recessed and windowed distance scale marked in feet and inches. A depth-of-field marker is provided, but is only marked for ƒ/32. Given the focal length of this lens, this is hardly a surprise (the depth-of-field for any aperture setting less than ƒ/32 is hard to register on such a limited scale).

The focus ring on the lens is compose of raised rubber ribs, and is about 1.25 inches wide. It has very nice feel, and with a travel of almost 180 degrees through the focus range, its smooth operation makes manual focusing very easy.

There are an impressive amount of switches and buttons at the disposal of the shooter, the majority of which are inset into a command panel along the left side of the lens barrel. From top to bottom, we have a 3-stage focus limiter switch, AF/MF selector, Image stabilizer selector (both activation and mode selection), and finally the focus preset system.

Given the weight of the lens (5.6 pounds) there is some discussion about the usefulness of image stabilization; there is only so long that most of us are going to hand-hold such a lens. The image stabilization system on the 300mm ƒ/2.8L is designed to work with tripods as well, especially useful as even on a tripod camera shake can be a problem with such a long focal length. Image stabilization comes in two flavors, mode 1 and 2, which allows stabilization to be introduced to counteract movement in both directions (mode 1) or just in the vertical, for panning actions (mode 2).

There has been some discussion about the focus preset system, in that the preset ring can be too easily depressed, leading to an inopportune re-focusing to the memory setting. Apparently it is possible to increase the friction of the switch to increase the pressure required to activate the system, but you'll have to take apart the panel to do so.

The 300mm ƒ/2.8 doesn't use a forward filter ring system, as the front element is huge. Instead, it employs a 52mm drop-in filter system, which can accept an internal polarizer as well as gelatin filters. The lens hood for the 300mm ƒ/2.8, the massive ET-120, is a plastic cylinder, 5 3/4 inches long by 5 3/4 inches wide. It attaches by means of a rotating locking knob. Don't lose this: it will set you back over $500 if you need a new one!

The lens comes equipped with a rotating tripod mount, which can easily be removed. Unfortunately there are no click-stops at 90 degrees for easy transitions between portrait and landscape-style shooting. However given the weight of this lens, you may be better off buying a Wimberly lens mount to allow for optimum support, and provides a better method for going between portrait and landscape shooting. You'll also need some serious tripod legs to support the whole package. This is the high-class problem with owning anything expensive of high quality; the accessories to use them properly also expensive, as well, but are almost required to get optimum performance.

Speaking of accessories, some allow you to get closer to your subject in a variety of ways: the 300mm ƒ/2.8 is compatible with Canon's EF12 and EF25 extension tubes, as well as 1.4x and 2x tele-extenders. With a 2x tele-extender attached, on a subframe body, the lens could produce an effective field of view of 960mm (but having a maximum aperture of ƒ/5.6).

Alternatives

Sigma 300mm ƒ/2.8 EX DG HSM APO ~$2,600
We haven't yet tested this Sigma comparable. It is only slightly smaller and lighter, takes smaller drop-in filters, and has an additional diaphragm blade in the aperture (9 vs Canon's 8). Does not employ an image stabilization system.

Tamron SP AF 300mm ƒ/2.8 LD IF ~$2,900
Tamron also produces a comparable lens; we have not tested it. It is heavier than the Canon 300mm, takes smaller drop-in filters, and has an additional diaphragm blade in the aperture (9 vs Canon's 8). Does not employ an image stabilization system.

Canon EF 300mm ƒ/4L IS USM ~$1,200
If you don't need the maximum aperture of ƒ/2.8, consider saving yourself $3,000 and look at the ƒ/4 version of the 300mm L-series. We haven't tested it, but user reviews are very positive. Also employs Canon's twin-mode image stabilization system and takes regular 77mm filters.

Conclusion
Optically, the 300mm ƒ/2.8L IS produces extremely sharp images, almost free from chromatic aberration, distortion and corner shading. This is most evident when used on a sub-frame sensor body and larger apertures over smaller. On a full-frame sensor body, the lens is almost as good, though corner shading is a bit more evident at ƒ/2.8 and sharpness, while very impressive, is never ''tack-sharp'' across the frame. It's been said before in other reviews, but is worth saying again - it doesn't get much better than this.

For the focal length achieved, Canon has really worked wonders with this lens, which offers excellent performance not only optically but with all the options available to really optimize the photographer's shooting performance. I suspect buyers looking for a lens in this category will actually have some difficulty settling on the right focal length, given that Canon has such great choices between 300mm-600mm. When you're looking to drop several thousand dollars on a lens, you want to be sure you're buying the right one. The most we can offer is if you settle on the 300mm ƒ/2.8L IS, your only regret will be that you didn't buy it sooner.

Sample Photos

The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.

Still Life shot

VFA target

As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.