The Canon EF 11-24mm f/4L USM launched as the world’s widest-angle rectilinear zoom lens, overtaking the Sigma 12-24mm f/4 DG HSM | A by a single millimeter in its shortest focal length. The 11mm focal length delivers a monstrous 126-degree viewing angle, measured on the horizontal of the image frame. It’s only marginally bigger and heavier than Sigma’s 12-24mm ‘Art’ lens, which almost matches the Canon with a maximum viewing angle of 122 degrees.
Mount: Canon EF (full-frame)
Image stabilization: No
Lens construction: 16 elements in 11 groups
Angle of view: 126-84 degrees
Diaphragm blades: 9
Minimum aperture: f/22
Minimum focusing distance: 0.28m
Maximum magnification ratio: 0.16x
Filter size: N/A
As you’d expect at the price, this L-series lens has impeccable, fully professional-grade build quality. The optical path includes one UD (Ultra-low Dispersion) and one Super UD element, plus four aspherical elements. Three different types of coatings are employed to minimize ghosting and flare, including Canon’s high-tech ASC (Air Sphere Coating) and SWC (SubWavelength Coating). As with most recent Canon L-series lenses, this one features multiple weather-seals, as well as fluorine coatings on the front and rear elements.
As usual in ultra-wide-angle lenses, the hood is integral, which gives physical protection to the extremely bulbous, protruding front element. There’s a gelatin filter holder in the mounting plate at the rear but, if you want to use regular filters, you’ll need a specialist system like the Lee Filters SW150 Mark II.
The autofocus system is very quick and quiet, based on an ultrasonic ring-type drive with a high-speed processor and optimized algorithms. There’s no image stabilization but that’s generally not too much of an issue at the short end of the zoom range, where you can typically get away with shutter speeds as slow as 1/10th of a second in handheld shooting.
Centre-sharpness is very good at all focal lengths but the Canon loses out slightly to the Sigma 12-24mm for corner-sharpness at the short end of the zoom range. Control over distortions and color fringing is pretty good but, again, the Sigma has the edge in minimizing these aberrations.
We run a range of lab tests under controlled conditions, using the Imatest Master testing suite. Photos of test charts are taken across the range of apertures and zooms (where available), then analyzed for sharpness, distortion and chromatic aberrations.
We use Imatest SFR (spatial frequency response) charts and analysis software to plot lens resolution at the center of the image frame, corners and mid-point distances, across the range of aperture settings and, with zoom lenses, at four different focal lengths. The tests also measure distortion and color fringing (chromatic aberration).
Centre-sharpness is excellent even when shooting wide-open at f/4, throughout the entire zoom range. At 11mm, however, you really need to stop down to f/8 if you want impressive sharpness out to the edges and corners of the frame.
There’s fairly minimal color fringing in the mid to long sector of the zoom range but it can be rather noticeable towards the edges and corners of the frame at the short end.
Barrel distortion can be very noticeable at the shortest focal length but it’s fairly negligible from medium to long zoom settings.
It’s a very pricey zoom but if you want a really extreme viewing angle from a ‘genuine’ own-brand Canon lens, it fits the bill. If you’re happy to mix and match brands, the Sigma 12-24mm Art lens is a better buy at around half the price.