Roughly two-and-a-half years ago Canon replaced the legendary EF 50mm f/1.0L USM with the EF 50mm f/1.2L USM. While its predecessor was the fastest (and one of the most expensive) mass-production lens ever made, by sacrificing two thirds of a stop, Canon was able to reduce the price of the lens significantly, although the 50mm f/1.2L USM remains very expensive for a standard prime lens.
There are currently three 50mm lenses in Canon's line-up: the EF 50mm f/1.2L USM (RRP $2499), EF 50mm f/1.4 USM (RRP $699) and the EF 50mm f/1.8 II (RRP $149). They're all quite different and targeted at different sectors of the market. The L-series represents Canon's flagship professional lens range and offers superior build quality (it's the only one with dust and moisture resistant construction) plus the highest image quality of the trio, as you'd expect from its price tag.
Canon's three 50mm lenses. From left: EF 50mm f/1.2L USM, EF 50mm f/1.4 USM and EF 50mm f/1.8 II. (Source: Canon.)
Like other EF lenses, this lens can be used with both 36 x 24mm and ‘APS-C-sized' sensors, delivering its designated 50mm focal length with the former and the equivalent of 80mm with Canon's entry-level and ‘pro-sumer' DSLRs, which have sensors with a 1.6x crop factor. With the latter, the large maximum aperture makes it a useful portrait lens.
Compared with zoom lenses, the optical design of this lens is relatively simple, with eight elements arranged in six groups. One aspherical element is included to minimise common aberrations. Super Spectra coatings have been applied to suppress flare and ghosting and the lens elements have been shaped to minimise the effects of reflection off the image sensor in order to ensure sharp, contrasty images.
The Canon EF 50mm f/1.2L USM lens. (Source: Canon.)
The lens barrel is made from metal and high-grade polycarbonate. It has a smart semi-matte black finish plus the characteristic narrow red ring that identifies an L-series lens. The red ring lies just in front of the 14 mm wide focusing ring, which sports a ridged rubber grip.
A single AF/MF switch is located on the lens barrel, left of and behind the distance scale, which lies beneath a transparent window. Distances are shown in metres and feet and range in seven steps from 0.45 metres to infinity. A depth-of-field scale is engraved on the lens barrel immediately behind the distance scale and, unusually for a modern lens, infinity compensation and infrared compensation marks are also provided.
The infinity compensation mark enables photographers to adjust focus for slight shifts that can occur with changes in temperature. For the normal temperature range (up to approximately 30 degrees C), the infinity mark should be aligned with the vertical line on the L-shaped mark. In higher ambient temperatures, manual focusing through the viewfinder is recommended when shooting distant subjects.
The infrared index corrects focus for shooting with monochrome infrared film. Its main relevance is to film SLR users since it doesn't apply to infrared photography with digital cameras.
Unlike most DSLR lenses, the minimum aperture on the EF 50mm f/1.2L USM is f/16; not f/22. Photographers shouldn't feel short-changed by the lack of smaller apertures because they've gained many more at the opposite end of the scale. The f/16 minimum aperture also makes this lens less prone to diffraction limitations at small aperture settings than other lenses - an advantage that became obvious in our Imatest tests.
The EF 50mm f/1.2L USM maintains a constant physical length during focusing and the front element doesn't rotate, allowing use of angle-critical attachments. However, the inner lens tube moves a few millimetres back and forth as the lens is focused. Consequently, Canon advises users to fit a protective filter to prevent dust and moisture from getting in. Without such sealing, the dust and moisture resistance is compromised.
Autofocusing is driven by a ring-type Ultrasonic motor (USM), which uses high-frequency vibrations to focus the lens quickly with near-silent operation. A built-in high-speed CPU and improved AF algorithm contribute further to AF speed and effective holding torque prevents focus over-shooting. Full time electronic manual focus override is available so users don't need to switch out of AF when fine-tuning focusing.
Unlike many Canon lenses, this lens has no built-in stabilisation. However, its handling qualities and wide maximum apertures make it easy to use slow shutter speeds in dim lighting with minimal risk of camera shake. Eight diaphragm blades close to a circular aperture to ensure attractive bokeh.
The lens can also pass distance information to the E-TTL II flash systems in compatible EOS DSLRs to ensure accurate flash metering. Supplied accessories include front and end caps plus a cylindrical lens hood and a soft carrying case.
Handling
Despite being relatively heavy, the review lens was a good match for the EOS 5D and EOS 40D bodies we used for our tests, although it may be a little heavy for Canon's lighter, entry-level bodies. The overall design gave the lens a nice balance on our testing cameras and the focusing ring was wide, easy to reach and moved silently and very smoothly.
The large f/1.2 maximum aperture provides bright viewing for low-light photography and is ideal for differential focusing. However, with some subjects, the shallow depth of focus at f/1.2 can create its own problems - as illustrated in the sample images below. There are often times when stopping down a little will provide better pictures.
In addition, because more light enters the lens, it's easier to compose shots and there's more information for the AF system to work with. Despite the absence of image stabilisation, we were able to use shutter speeds as slow as 1/6 second and have more than 50% of shots acceptably sharp.
Performance
Our Imatest tests on the review lens were done with a Canon EOS 5D body, which has a sensor that covers the 36 x 24 mm imaging area for which this lens was designed. Many of the sample images were also captured with this body, although we also captured some test shots with an EOS 40D body to show how the lens performed with a smaller sensor.
Regardless of which camera we shot with, focusing was acceptably fast and accurate with the review lens, despite the lens design (which requires a sizeable amount of glass to be moved back and forth through just under 10 mm). But it was seldom instantaneous and not comparable with Canon's highly-responsive, rear-focusing lenses.
Picture quality was generally admirable, with the 5D body providing the expected quality edge over the 40D. Most test shots taken with the 40D benefited from a little additional unsharp masking in Photoshop post-capture.
Shots taken with the f/1.2 aperture provided the most dramatic results from this lens although, with the very small depth-of-field at this aperture, focusing must be accurate. When used with apertures between f/4 and f/9, image quality was outstanding and test shots from both camera bodies were sharp edge-to-edge.
Imatest showed the review lens to be a stellar performer in some respects, although there were areas in which its performance was at or below average. Our tests found little difference between centre and edge resolution throughout the focal length range of the lens, which is unusual for such a fast lens.
Highest resolution occurred between f/5 and f/8 with the lowest resolution between f/1.2 and f/3.5. But there was less than 400 points of difference between these extremes, which is also unusually small. The graph below shows the results of our tests.
Lateral chromatic aberration was consistently low throughout the aperture range. Although it never strayed into the ‘negligible' band, it remained near the upper edge of the ‘low' band at all focal length settings, with the lowest value (0.58% of distance to corner) recorded at f/5.6. Nevertheless, we found no obvious coloured fringing in any of the test shots we recorded.
Vignetting was obvious at the widest apertures but gone by f/3.2. Rectilinear distortion was negligible and the lens proved quite flare-resistant. The close-up capabilities of this lens are quite limited, due to a minimum focusing distance of 45 cm. However, we were able to shoot some attractive pictures of relatively large flowers, particularly when the review lens was used on the EOS 40D body.
Bokeh at wide aperture settings is one of the main reasons photographers gravitate towards fast prime lenses and we found the review lens to be a superior performer. At apertures between f/1.2 and f/2.8, out-of-focus highlights appeared smooth, circular and attractively uniform in tone and ‘texture'.
Stopping down further, the transition zone between sharp focus and blur retained its smoothness across most of the image frame but deteriorated slightly near the edges. We also found traces of coloured fringing along the inner edges of out-of-focus highlights.
Buy this lens if:
- You want a fast lens for available light photography and require high resolution across the aperture range.
- You'd like an ultra-fast portrait lens for a camera body with an APS-C sized sensor (the 1.6x crop factor provides the equivalent of an 80mm focal length).
- You need a standard lens that can handle exposure to dust, spray and light showers.
- You require distortion-free images.
Don't buy this lens if:
- You can get by with one of the cheaper (and slower) alternatives.
- You really need a zoom lens.
- You shoot lots of close-ups.
IMATEST GRAPHS
SAMPLE IMAGES
Taken with EOS 5D:
50mm field of view on a camera with a 36 x 24 mm image sensor. ISO 125, 1/500 second at f/8.
ISO 125, 1/500 second at f/1.2.
ISO 125, 1/250 second at f/1.8.
ISO 250, 1/50 second at f/8.
Vignetting at f/1.2;ISO 100, 1/8192 second.
Vignetting at f/2; ISO 125, 1/8192 second.
Distortion: ISO 125,1/664 second at f/4.6.
Portrait at f/1.8; ISO 400, 1/91 second.
Stabilisation test; ISO 400, 1/10 second at f/5.6.
ISO 125, 1/83 second at f/16.
Taken with EOS 40D:
80mm field of view on a camera with a 22.2 x 14.8 mm image sensor. ISO 200, 1/500 second at f/9.
ISO 200, 1/500 second at f/1.2.
ISO 200, 1/250 second at f/1.8.
ISO 800, 1/40 second at f/8.
Backlighting; ISO 200, 1/312 second at f/8.
Portrait at f/1.2; ISO 200, 1/160 second.
Stabilisation test; ISO 800, 1/6 second at f/9.5.