By any standards, this Canon EF 24mm f1.4 is a pretty specialised lens. It’s a fixed focal length optic in a camera world now dominated by zooms, and compared to the average zoom it’s also fantastically expensive. But it does have that f1.4 maximum aperture, and this gives it a two-stop aperture advantage over even a fast, pro zoom lens. There are two benefits to this. One is that it enables you to shoot in light that’s much dimmer than usual without risking camera shake (or without having to increase the ISO). The other is that it’s possible to create striking shallow depth of field effects, which is normally difficult with a wide-angle lens like this one.
It’s only a true wide-angle, though, when fitted to a full-frame DSLR like the EOS 1Ds Mark III or the EOS 5D Mark II. Like other Canon EF lenses, this can also be fitted to Canon’s smaller-format DSLRs, including the EOS 50D, 500D and so on. Here, though, there’s the usual 1.6x focal factor to apply. This means that on these smaller-format cameras, this lens is equivalent to a 38mm, though this makes it interesting all over again, because now it works as a fast ‘standard’ lens rather than as a wide-angle.
It might be an interesting lens, then, for photographers who own both sizes of body, or who have a smaller-format Canon and want to invest in ‘future-proof’ lenses which can also be used on a full-frame body if they decide to upgrade at some point.
That’s perhaps rather academic, though, since with a list price of just under £1,900, this is hardly an amateur lens. It’s far more likely to be considered by professional photographers who already use full-frame bodies. Even here, though, it’s going to have to deliver something special to justify a price tag like that.
Fortunately it does, on a number of levels. First of all, the definition, using one of Canon’s latest full-frame bodies (an EOS 5D Mark II), is quite staggering. The scale for our resolution charts normally stops at 2,000 line widths/picture height, since few cameras or lenses even approach that. Here, though, the resolution is way above this figure at every aperture except f1.4. The only reason the value drops below this level is because the edge definition wide open is a lot lower (our figures are an average of the lens’s centre and edge definition at any given aperture). Between f2 and f5.6, this lens delivered, in our tests, in excess of 3,000 line widths/picture height in the centre of the frame.
Away from the frame centre, the resolution was lower throughout the aperture range. This lens still delivers very crisp detail towards the edges of the frame, but it’s not at the same level as the centre. And in some shooting situations, this lens’s full resolving power may not be apparent at all. In very low light you’ll be working at or near the lens’s maximum aperture, and while the lens itself will still be sharp at these apertures, there’s so little depth of field that much of the subject will inevitably be out of focus. Also, in very dim light you’ll probably be shooting at marginal shutter speeds, and even tiny amounts of camera shake will take the edge off the definition. Indeed, while this is a fantastic lens for low-light photography, it might be even better with image stabilisation, though there may be technical reasons why this is not possible.
This lens’s outright resolution isn’t its only strength. Zoom lenses require optical compromises that produce unavoidable barrel and/or pincushion distortion, which will go unnoticed in many types of photography, but which sticks out like a sore thumb when shooting buildings or interiors. Prime lenses like this one, though, are simpler to the extent that distortion can be largely eliminated. This is a lens that produces genuinely straight lines despite its wide angle of view, and that’s a novelty if you’re used to the optical limitations of zooms. There’s not much chromatic aberration, either. It's visible to a degree in the high-contrast test charts used for the resolution tests, but scarcely noticeable in ordinary photography.
While a fixed focal length lens is limiting compared to a zoom, you do get used to it. It doesn’t take much to shift your position by a few feet, or to scout around for a better viewpoint – this can actually yield a more interesting perspective, which would otherwise have been overlooked.
The Canon EF 24mm f1.4 is an expensive and highly specialised lens, likely to appeal most to pros who can justify the cost. But even if you’re not and outright image quality is your priority, it’s got to be worth consideration. Final Verdict
This is an exceptional lens at, unfortunately, an exceptional price. It may seem an exclusive choice for pros, though for many the results will be worth the high cost
Canon EF 17-40mm f4.0L USM
It’s been around a while, then, but the arrival of cheaper full-frame Canons has made the 17-40mm interesting all over again, especially since the 21-megapixel EOS 5D Mk II now brings professional-quality imaging down to a (sort of) affordable level. Indeed, this is the camera we’ve chosen to test the venerable 17-40mm with to see if it’s still got what it takes.
While the price might seem steep, it does actually represent pretty good value. Any 17-40mm zoom is a pretty exotic and therefore expensive beast – remember, this is a ‘real’ 17-40mm and not a ‘digital’ lens where you have to apply a focal factor to work out the equivalent focal length. Zooms don’t come much wider than this, and although Nikon has a full-frame 14-24mm lens, it’s almost twice the price of this one.
The initial signs are good. The EOS 5D Mk II itself is capable of astonishing resolution and clarity of detail, and this lens appears able to come close to the limits of the 5D Mk II’s sensor, which is no mean achievement for a lens which is several years old. As we found in our test of the Canon EF 24mm f1.4 lens, we’ve had to move the scale on our resolution chart to accommodate the figures generated.
However, other users have remarked that the 17-40mm’s edge definition is disappointing, and this is borne out in our tests, lowering the overall figures. The centre definition is quite exceptional, but resolution drops off considerably towards the edges of the frame and you really need to stop down to around f8 before they start to catch up. The softer edges are especially noticeable at the shortest and longest focal lengths.
That is a disappointment. If you routinely shoot outdoors or on a tripod, where smaller apertures will be the norm, you won’t find much to complain about, but if you want to exploit this lens’s constant f4 maximum aperture, it’s something to be aware of.
This lens does have other good qualities, though. It’s quite compact, and the zoom and focus movements are both light and smooth. By comparison, Nikon’s 14-24mm f2.8, say, is a monster. Canon’s USM autofocus motors are as quiet here as they are on later lenses, and it’s a pretty sweet-handling lens all round.
It’s not the only full-frame super-wideangle zoom in the Canon range. There’s also the 16-35mm f2.8L USM II, but this has a list price of £1,690, which is practically twice that of the 17-40mm.
As long as you make some allowances for its mediocre edge performance at wide apertures, then, the 17-40mm f4L USM offers by far the cheapest way to discover the extraordinary visual effects of super-wideangle photography on a full-frame EOS body.
Not only that, here is a lens which can be used either on an EF-S format Canon or a full-frame model. What’s especially significant at this time is that full-frame lenses like this are an ideal investment for Canon users on the cusp of moving into full-frame. Final Verdict
The Canon 17-40mm’s optical performance might have its weak spots, but for a super-wideangle full-frame lens it’s good value
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