There’s no such thing as coincidence. A CameraStuffReview reader offered me the opportunity to test a Canon 50 mm f/1.2. Such a thing almost never happens. It’s a very unusual lens that is very difficult to make, and due to the high purchase price, you rarely encounter this lens. This time, I was extra-pleased with the offer, because I was just wanting to test the Sigma 50 mm f/1.4. Now I was able to test them at the same time.

Before we come to the young challenger, let’s review the old champion. The Canon 50 mm f/1.2L USM has the largest aperture of all Canon lenses that are currently available.

Canon EF 50 mm 1.2L USM and Canon 5D MK3

Canon EF 50mm f/1.2L USM @ f/1.2, 1/6400 sec, 400 ISO

Construction and auto focus

The high construction quality of the Canon L lenses is assumedly well known. The lenses are built like a tank. You have more than a half kilo of glass hanging on your camera if you use this standard lens. That is 4 times as heavy as the Canon 50 mm f/1.8, which is available for about 100 euros. You expect with a bright lens a bubble front lens that extends far to the front, but the reverse is true: the front lens lies hidden in the lens body.

The USM AF-motor of the Canon 50 mm 1.2L is fast and silent and can at any time be overruled by manually focusing with the focus ring on the front of the lens. That is sometimes handy – for example, with the practice shot above, where the point of focus, at the bottom left, lies outside the reach of the AF sensors. At f/1.2, the focal depth is very small. Even if you think that you’ve aimed at the same point twice, there are sometimes differences visible in practice shots. If you want to focus precisely on the right point, then Liveview (and the use of a tripod) is the best method.

The Canon EF 50 mm f/1.2L is weather-resistant – not water-tight – and comes with a large, cylindrical sun hood and a soft cover.

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Lens corrections

We test all lenses in two ways. First, we save a jpg file (standard image style) in the camera with the highest possible quality, with all available lens corrections applied. In this case, we corrected for vignetting and chromatic aberration. This correction is only available for Canon lenses. This is the score for anyone shooting in jpg: WYSIWYG. What image quality do I have after these corrections are applied?

In addition, we analyze RAW files, where no editing (also no sharpening) has taken place.

This score gives you the best impression of the performance of test camera and lens. This is the best score to use for judging the quality of the lens design.

Vignetting

In particular, at full opening, vignetting is visible, but to be honest we hadn’t expected any different. At aperture f/2, there is only a half stop of vignetting left, and you can assume that in the vast majority of cases, that’s not visible. The lens corrections cut the amount of vignetting in half at f/1.2, but even after correction there is visible vignetting left over. This is of course simple to correct with software in Photoshop if that’s needed.

Move your mouse over the image to see the vignetting in uncorrected RAW files.

Canon EF 50mm f/1.2L USM @ f/1.2, 1/1000 sec, 400 ISO

Distortion

With 1% barrel-shaped distortion, the Canon 50 mm 1.2L lands in the middle among 50 mm lenses, even if we include the tests of zoom lenses. It is visible, but this lens will rarely be used in applications where it will be disturbing.

Flare

Lenses have more trouble on digital cameras with internal reflection than on analogue cameras. That comes from the sensor, which reflects part of the light. In this standard lens, Canon has applied Super Spectra coatings to limit flare and ghosts as much as possible. According to Canon, these coatings also contribute to a natural color balance and an increase in the contrast for lifelike, high-value shots. It works very well, but it’s not perfect.

With direct backlighting, you sometimes find flare and ghosts, such as the green ghost in the picture shown here.

Sharpness

Canon EF 50mm f/1.2L USM @ f/1.2, 1/15 sec, 3200 ISO

The picture above is a cut-out from a picture made with the illumination of a street light. In those situations, it’s nice to use a low-noise, full-frame camera. The viewfinder remains clear, thanks to the high brightness. Despite the full opening, the image is still rich in contrast.

Chromatic aberration

Lateral chromatic aberration, red and blue edges at sharp contrast transitions in the corners of the image, is visibly present in the RAW files. If you use the lens corrections of the camera, this form of chromatic aberration is absent from the jpg files.

Longitudinal chromatic aberration, color bokeh or spherochromatism are various understandings of the same phenomenon that appears with practically all bright lenses: green edges at sharp contrast transitions behind the focal point and magenta edges at sharp contrast transitions in front.

While you only see chromatic aberration in the corners of the image, color bokeh appears across the entire image. It is also more difficult to correct with software. The Canon 50 mm 1.2 has visible trouble from this phenomenon, as you can see in the picture shown here. It will not always be noticeable, and it’s an outstanding tool for making sure that you’ve focused well. Because this lens has so little focal depth at full opening, the zone without green or magenta color bokeh is very limited. With a black-and-white test card (or our LensAlign setup), you immediately see from the color bokeh whether there is front-focus or back-focus. Our test example fortunately had no trouble with front-focus or back-focus.

Bokeh

The Canon 50 mm f/1.2 has a round-shaped aperture with 8 aperture lamellae for excellent background blur/”bokeh”. Like Photozone, we found that the bokeh was especially beautiful at short testing distances (like we use in our standard test setup). Due to the high vignetting, in RAW files the bokeh is not round, but has the shape of cat eyes. That is not only the case in the corners, but in a large area of the image. In the jpg files, vignetting is corrected and the bokeh is more – but not perfectly – round, such as you see in the image below. An onion pattern is also visible. Overall, a beautiful bokeh, but we didn’t expect anything else.

In the practice shots with subjects at a greater distance, the bokeh was sometimes not smooth (move your mouse over the image on the right; you also see chromatic aberration), and our experience here was similar to that of Ken Rockwell: this is not always the dreamy background that you hope for.

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Look in our list of all tested lenses or the lenses we’ve tested with a Canon mount to compare the performance of this lens with that of other lenses.

Advantages

• Extremely high brightness
• Extremely little focal depth
• Super-solidly built
• Up close, a beautiful bokeh and soft, dreamy character at f/1.2

Disadvantages

• Expensive
• Heavy

It appears that the lens errors increase by a factor of 10 with each stop that a lens becomes brighter. Up to f/2.8, that’s not such a problem, but below that, it becomes visible. That’s why it’s so difficult to build a good, bright lens. The use of expensive glass types, in large amounts, makes this kind of lens extremely expensive. If you only judge this lens for sharpness, then there are less expensive, slightly less bright alternatives. On the other hand, the great expense in buying a lens is for its beautiful blur.

In recent years, the manufacturers have made enormous progress in the design of lenses. Would that also apply for this kind of specialist high-end lenses? Our test of the Sigma 50 mm 1.4 Art will appear shortly; we tested it under the same conditions on the same camera. Then we’ll know more.

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