A Canon 50 mm f/1.2 lens is not the most obvious choice of lens to use on a camera with an APS-C sensor. Even so, we are routinely asked how well a Canon EF lens performs on a camera with an APS-C sensor. And for every bokeh enthusiast, the extremely high brightness of this high-quality L-lens provides the ability to isolate your subject from the background, without having to switch to a camera with a full-frame sensor. Further, this test is interesting as a future ‘benchmark’ for the other Canon 50 mm lenses, which we haven’t yet tested as of this writing. Thus, when during our test of the Canon 50 mm f/1.2 on a Canon 5D MK3 we had a Canon 50 mm f/1.2L available, we also made measurement tests with our Canon 650D.

Canon EF 50 mm 1.2L USM and Canon 650D

Construction and auto focus

The high construction quality of the Canon L-lenses may be assumed to be 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’s 4 times as heavy as the Canon 50 mm f/1.8, which is for sale for about 100 euros. You expect with a bright lens that it will have a bubble lens protruding forward, but the reverse in the case: the front lens element lies completely within the lens body.

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

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

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Lens corrections

We test all lenses in two ways. First we sage 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 is the score for those who shoot in jpg: WYSIWYG. What image quality do you have after applying these corrections?

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

This score gives the best impression of the performance of test camera and lens. This is the best score on which to judge the quality of the lens design.

Vignetting

Only at full aperture is vignetting visible. The lens correction reduces the amount of vignetting at f/1.2, but even after correction there remains clearly visible vignetting. At aperture f/2, there is already less than half a stop of vignetting remaining, and as you can imagine, that’s not visible any longer. That is of course simple to correct with software in Photoshop, if that’s needed.

Distortion

With less than half of one percent barrel-shaped distortion, in practice you don’t have to worry about any distortion with the Canon 50 mm 1.2L. It may only be visible in critical applications such as reproduction photography or architectural photography, but this lens will rarely be used for applications where it will be disruptive.

Flare

Lenses have more trouble on digital cameras with internal reflections than on analogue cameras. This is caused by the sensor, which reflects part of the light. Canon has applied Super Spectra coatings in this standard lens to limit flare and ghosts as much as possible. These coatings also contribute, according to Canon, to a natural color balance and high contrast, for lively, high-quality shots. It works well, but it’s not perfect.

With direct backlighting, you sometimes find both 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 field of view of a 50 mm lens on a camera with an APS-C sensor compares to the field of view of an 80 mm lens on a camera with a full-frame sensor. If you take a picture that doesn’t quite fill the frame, this can be used due to the beautiful bokeh quite well as a portrait lens. Because on a camera with an APS-C sensor, you still have a very beautiful bokeh, thanks to the extremely high brightness of the Canon 50 mm f/1.2L.

Chromatic aberration

Lateral chromatic aberration, red and blue edges at sharp contrast transitions in the corners of the image, is visible in the RAW files. If you have turned on 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 different names for the same phenomenon, which arises with practically all bright lenses, and thus with the Canon 50 mm 1.2L as well: at full aperture, you can see green edges at sharp contrast transitions behind the point of focus and magenta edges at sharp contrast transitions in front of it. As soon as you stop down, this phenomenon disappears.

Bokeh

The Canon 50 mm f/1.2 has a round-shaped aperture with 8 aperture blades 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.

Look in our list of all reviewed lenses or the lenses we have reviewed with a Canon mount in order to compare the performance of this lens with other lenses.

WYSIWYG score: This table shows the performance of this lens if you save files in the camera as jpg, where you have all available in-camera lens corrections applied (chromatic aberration and vignetting). This score gives you for this lens/test camera combination: “What you see is what you get”. 

test camera: Canon 650D

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Pure RAW score: This table shows the performance of this lens if the file is saved in the camera in RAW format. This score approaches the intrinsic quality of the combination of lens and test camera. If you use Photoshop, Lightroom or SilkyPix for the conversion of RAW files, then the RAW scores are the same as the jpg scores. 

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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

In recent years, the manufacturers have made enormous progress in the design of lenses. You see that in the scores of this high-quality Canon lens. The performances are good, but for this price you might expect more. If you have a Canon camera with an APS-C sensor, and you find the sharpness of images important, then you can choose a cheaper Canon 50 mm lens with an easy heart. The dreamy character of this lens at full aperture is really unique. You can use that to distinguish yourself from other photographers. With the extremely high brightness, this lens on a camera with an APS-C sensor can, in terms of bokeh, compete with many bright lenses on a camera with a full-frame sensor. If you have a Canon 7D or Canon 70D, then a second-hand Canon 50 mm 1.2L might be a fun addition to your lens assortment for playing with the bokeh.

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