Lens Comparison: Sigma 50mm f/1.4 ART vs Canon 50mm f/1.2L

All of Sigma’s new “Art” series lenses have been impressive, as we’ve already seen in my comparison of the 35mm f/1.4 Art series lens, and the Sigma 50mm f/1.4 Art holds up that tradition. But how does it compare to Canon’s more expensive, larger aperture “L” model?  In last week’s comparison with the Canon f/1.4, we saw that the 1.2L has it’s share of problem areas, making this an interesting question.

To begin with, there’s the price difference:

On Amazon.com, the current price for the Sigma is $949 and the Canon is $1349. At B&H, the Sigma 50mm f/1.4 “Art” costs $949, while the Canon 50mm f/1.2L costs $1349 with the current mail-in-rebate.

So, the Canon has about a $400-600 price difference to justify. How does it do?

Resolution & Sharpness

Both lenses have excellent center resolution, though the Sigma is better from wide-open until around f/2.8. The Canon’s chromatic aberrations make that difference more pronounced between f/1.2 and f/2.8 in high contrast situations, but that does not appear to be the extent of the cause.


However, the Sigma performs much better away from the center of the image, and particularly at the borders, where the Canon’s image quality can be quite bad, especially at large apertures. At f/5.6, the Canon starts catching up to the Sigma, and at f/8, the differences at the borders of the frame are minimal.

Download the RAW Files


  1. I shoot a Sigma 50mm f1.4 Art on a 6D, after having really enjoyed the previous iteration of the 50 1.4, and I could not be happier. I looked at the bench tests of the 1.2L vs the 50 Art on Dxo Mark, and then didn’t have to think twice when I saw the price difference. I would rather start sharp, and add glow or cream or whatever than start soft, and have nowhere else to go.

  2. Matthew

    One more thing — while reviewing the Seattle images in LR using the ‘Show Focus Point’ plugin, I noticed that while you used Live View for both sets — the plugin data suggests you switched from AF to Manual focus when you shot the Sigma images. The focus point for the Canon images appears to have been the center of the frame, but the plugin suggests the focus point for the Sigma images was the Space Needle. If this is correct, what was the rationale for making the changes?


    1. If there was a different focus point, it was probably just because I accidentally moved it between sets… that happens sometimes if I bump the selector. At that distance, it wouldn’t matter where in the frame the AF point was… but it’s not something that I would have done on purpose. And I certainly would not have used manual focus… that sounds like a metadata mistake, although I suppose there’s an outside chance that it was a mistake on my part. That’s a good question.

      I’m in Croatia right now, and don’t have access to my whole photo library, so I can’t check the whole set for clues… but usually I shoot with one lens taking two or three shots at each aperture walking up from the maximum to about f/16, then back to the maximum aperture again so that I have several shots at each aperture (and if the light is changing, then it gives me a better chance of getting two that are similar between lenses). Then I switch lenses and do the same thing with the next lens. Sometimes, I get a little obsessive, and I then wait 10 minutes and do the same thing over again (usually if I think there are problems with the lighting), and then I may end up comparing a shot from one set to a shot from the next set, etc, depending on what I think will be the most accurate comparison. But it’s been too long for me to remember exactly what the process was with those lenses at that location :-)

  3. Matthew — thank you for producing a candid, non-biased and very straightforward comparison between the Sigma Art 50 and Canon 50L. I especially enjoyed the luxury of being able to download your RAW files and view the images like something I (personally) had just shot. What a telling set of images!

    The Sigma images are simply stunning in terms of overall sharpness with very pleasing contrast. I also beleive the comparison highlights just far optical technology has progressed since the 50L debuted in 2006.


  4. I really like the video but when it come to photo samples I’m bit confusing my self coz there are some mistakes in the photos description or the information. I think overall it’s a good video. May you can correct it and renew your video.

    1. Sorry about the label issues. If you watch the video with annotations turned on, it should correct all of them. They should appear by default if you watch on your computer, but I know they’re generally turned off by default on mobile devices.

      There are, unfortunately, several reasons why uploading a new video isn’t practical. But I’ll certainly be more careful in the future!

      As Ever,
      Matthew Gore

  5. Matthew, you did not make any mention of the setup you are using. Looking at the photos I am curious how you tested them. All photos you took with the Canon lens look like they have some kind of haze over them. You couldn’t get that kind of haze with any “L” lens that was clean, calibrated and placed on a clean and adjusted full frame camera body; it just doesn’t happen. I have borrowed the 1.2 lens and shot several hundred photos trying to determine how well I liked the lens. I do not have access to the Sigma, so I can’t compare, but not a single photo I took on a Canon 5D Mk III or a Canon 70D (APS-C) came through with any of the haze shown in your photos. The consistent reproduction of these artifacts leads me to believe either you had a dirty lens, camera or the lens was not calibrated properly. While I cannot speak to a comparison, I can say your results from Canon “L” quality glass are not representative of any photo I have taken with any “L” glass and, in particular, the borrowed f/1.2 lens. However, thanks for the review. I appreciate the time you took to look at the lenses for us, but I would suggest with such consistently poor image quality you should check to see where you have some malfunction or cleanliness issue. Perhaps some assembler at the factory touched an interior lens or something.

    1. Hi Mike,

      Actually, at about 1:40 in the video, I describe my setup and methodology. These were all shot RAW and not adjusted for contrast/black point/white point, so they’re not as contrasty as you might expect from shooting JPGS, but I assure you, there was nothing wrong with my 50mm f/1.2L . It’s been thoroughly tested, and even though I chose some low-contrast test scenes (on purpose), this lens performs consistently with the numerous others that I’ve tested. I’ve also provided RAW files for you to download, if you’d like to inspect them more closely.

      – Matthew

  6. Thankyou very much for your concise, pleasant and unspruiky reviews :).
    In this review as both these lenses are representive of a kind purist photography I had a feeling a usually esoteric aspect of lens character could also be included. The 1.2L is hardly for conventional landscape. Sure it is import to know its limitations, however for big bucks its singular virtue is to an old fashioned painterliness, it makes people look nice in portraits, or perhaps if compared to a Leica Noctilux how well does it render colours in a scene in late twilight? If the Art lens gives the Noctilux in this domain a strong show, then they have aced it haven’t they? Then there is the pricey Otus to consider.

  7. Matthew, Thanks for your great lens reviews. Very helpful and useful.

    Did you get my contribution a few days ago. I saw that it went to YouTube and not to you, so I’m not sure how that really works.

    Keep up the good work!

    1. Hey Dave,
      I’m glad you’re finding these lens reviews helpful! This particular one has been a bit problematic to publish, but they were fun lenses to put through the paces.

      I may very well have received your support a few days ago… YouTube doesn’t give me any information about who contributes, they only tell me the amount… but I did receive my first donation, so if that was you, thanks! This “Fan Support” system through YouTube is still a bit confusing; I only just today figured out where they show that information. They don’t send me an email or notification of any kind, which I think is odd.

      In any case, I’m up to 3 now, and I’m starting to believe that the support will really make a difference. Thanks again! If you have any ideas for future videos, let me know, and I’ll see what I can do! :)
      – Matthew

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