Yet Another Sigma 50mm Art Post

Published April 30, 2014

I suspect I’ll never be on any manufacturer’s “early review copy” list for new lenses. There are already plenty of good early lab reviews on the eagerly awaited Sigma 50mm f/1.4 Art lens at SLRGear, Lenstip, and DPReview, among others. So when we received our first Sigma 50 f/1.4 Art lenses for rental stock I really didn’t plan on posting about it.

But I always think it’s worthwhile to review multiple copies of a lens bought off-the-shelf from retailers. Plus, we’ll have our new MTF bench installed in another week or two, and I want to do some comparisons using the bench versus Imatest, so when we got our first seven copies of the Sigma 50mm f/1.4 Art in yesterday I compared them with Imatest. I decided I might as well post the results, even though I’m a bit late to the party.

The comparison most people are making is with the Zeiss 55mm Otus, because the Sigma Art and the Otus are both newly designed, excellent lenses. I added the Canon 50mm f/1.2 into the mix, since I suspect some 50mm f/1.2 shooters are wondering if they should migrate to the new Sigma. I choose a beat up and battered two-year-old Canon for the photo below, just to emphasize that it goes into this contest like a prize-fighter coming out of retirement for the fifth time. True, it was released in 2006, but even that was something of a comeback. The optical design dates back to the early 1980s.

As always, this isn’t a complete lens review, just lab testing and comparisons on multiple samples.

Tale of the Tape

The Canon has a simple double Gauss design with 8 elements in 6 groups. The Sigma has 13 elements in 8 groups, while the Otus has 12 elements in 10 groups.

Left to right: Zeiss 55mm Otus, Sigma 50mm Art, Canon 50mm L


The other specifications are pretty clear: the Zeiss is really big and really expensive, the Canon is smallest and goes to f/1.2, the Sigma is easily the least expensive and middle-sized.

  Canon 50mm f/1.2 L Sigma 50mm f/1.4 Art Zeiss 55mm f/1.4 Otus
Weight (lb)1.31.792.27
Length (in)2.583.935.66
Aperture Blades899
Filter thread72mm77mm77mm
Price $1619$949$3990

This isn’t a lens review, but for someone who does a lot of manual focus, I absolutely love the smooth, long-throw focus ring of the Zeiss. The Sigma Art manual focus ring is really excellent, too — very smooth and accurate. After using those, the Canon’s manual focus ring feels like a greased pig.

The Sigma’s autofocus was quick and accurate on a 5D Mk II and 6D in good indoor lighting, but I didn’t stress test it under difficult conditions or with moving targets. You’ll want to read some hands -on reviews to get better information about that. The Zeiss’s autofocus system, of course, isn’t.

Let’s Roll Some Numbers

Every review I’ve seen so far states the Sigma Art’s resolution numbers are very close to the Otus. I’m not here to argue, as the graph below shows. (Testing distance was at 10 feet for the Sigma and Canon, 11 feet for the Zeiss.)

MTF50 in Line Pairs / Image Height for 7 copies of each lens, all tested at f/1.4


I imagine, just like me, you notice there’s a bit more spread for the Sigma copies than either the Canon or Zeiss copies (especially when you consider the Sigma copies were all new-in-box and the others were used copies off of our shelves). I think this is just fairly normal sample variation — if I had 30 copies instead of 7, we’d probably be seeing similar pattern sizes for all 3 lenses. But I won’t be comfortable with that answer until I have the chance to test another 15 or 20 copies. We won’t be getting anymore this week, (they are understandably hard to come by right now) so I’ll add further testing as an addendum to this article in a week or so. I did, of course, repeat these test runs multiple times to make sure there wasn’t any testing problem, and there wasn’t.

Remember also that we’re looking at hair-splitting MTF numbers here. Even the two “lower” Sigma copies are clearly outresolving all of the Canon copies, and the Canons were shot at f/1.4 to make sure the playing field was even. Carefully testing on an ISO 12233 chart showed all of the Sigma lenses resolved well with no soft corners or astigmatism, which is the main reason I think this is just sample variation.

Stopping Them Down

Watching how the lenses behave as they are stopped down is interesting. The graphs below show center, weighted average, and corner resolution (corner numbers are the average of horizontal and vertical readings in each corner) for each type of lens from wide open to f/11 on 5D Mk II cameras. The Canon is shown at both f/1.2 and f/1.4, the other two, of course, start at f/1.4.



The Zeiss corners peak a little earlier than the Sigma (at f/4), but at f/5.6 resolution for those two is virtually identical. The Sigma corners are even a bit better at f/5.6 The Canon hangs with the other two lenses in the center, but its corners never sharpen up quite as well as the other two do.


I really don’t have a lot to add to what has already been said. From a resolution standpoint the Sigma is nearly as good as the Zeiss Otus, and clearly better than the Canon 50mm f/1.2 L. It does this at a price point far lower than either of the others. There may (or may not) be some sample variation, but I won’t know for certain until we’ve tested a lot more copies – but even the weakest two copies of the Sigma were clearly better than any of the Canon’s.

Of course, people buying wide aperture 50mm lenses are at least as interested in bokeh, autofocus accuracy, color rendition, and a number of other traits as they are in resolution. More and more images are being posted every day to let you assess that before making a decision. But assuming those things all turn out acceptable to you, it’s hard to imagine a better value at 50mm than the Sigma 50mm f/1.4 art.

Roger Cicala


April, 2014

Author: Roger Cicala

I’m Roger and I am the founder of Lensrentals.com. Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

Posted in Other
  • Steve Barret

    I recenty switch to mirrorless camera and im just contented with it. Stock lenses are really good, and the brilliance on its nightshots are amazing.

  • Jarno

    Hi Roger,

    Thanks for all the fantastic posts. Sigma 50mm A has more complex optical design vs. Canon/Nikon 50mm lenses. Does this show up in Sigman’s reliability record yet?


  • Hi Roger,

    That post here together with http://wordpress.lensrentals.com/2013/06/sigma-optimization-pro-and-usb-dock are most valuable for any Sigma 50mm f/1.4 Art owner. Especially some comments to them. 🙂

    I did my own test. Canon EOS 6D plus Sigma 50mm f/1.4 Art


    What do you think about my copy of that lens? Is any adjustment needed and where (at which length)? Right now I don’t using any AF adjustment in body and/or with Sigma USB DOCK which I have it. Everything is on 0.

    As you see in albums starting with names “Live View…” and “Viewfinder…” there’s difference at 0.4m how lens parked. AF with viewfinder and lens is straight on dot between 0 and 4 and picture is in focus. AF with Live View and lens is slightly before that dot and… something like backfocus? Is it normal?

    In normal life I don’t care about f1.4, I using mostly range f2.8-f8 but I wanna know that isn’t some mechanical fault.


  • tom

    Hi! thanks for the test! however I’m currently a sony A-mount user. I chose this for personnal taste of EVF and spectacular sony-Zeis lens. On this point I was wondering if we might have the luck to see the very quite new 50mm 1.4 Sony Zeiss SSM compared and tested with those lenses :p. First impressions on this lens are kinda unanymous: very good, almost “imperial” for some, somewhat pricey, but never saw a direct comparison… I think that would be interesting if you had the opportunity to do that. ^^ cheers

  • Murat

    Roger, thanks for this thorough analysis. Sigma is certainly doing really well. However one thing I realized when comparing Sigma and Otus is the higher transmission of Otus. The difference is between 2/3 and 1 stop. So, while Otus is a real f1.4 lens, Sigma is more like a f1.8. Do you think this is one reason Sigma seems to come really close to Otus in performance?

  • Will

    Would you be able to put all of the MFT graphs in a single graph for each center, corners, and average? That way you can compare each lenses much better instead of having to scroll and second guess where each one goes to. We are comparing the lenses afterall, not comparing the sharpness of the lens in the corner and center.

  • Roger Cicala

    jintoku, I too, the median copy to make the curves with.

  • jintoku

    Roger, also, when you show the MTF-50 versus Aperture curves in comparison to the Zeiss&Canon, do you know if you used an average Sigma copy or better/worse than average?

  • jintoku

    Thanks, Roger. Would you consider the 50 Art variation great enough that it would be noticeable without your test setup for somebody with a D800E?

  • Max Berlin

    My bag has the Distagon 21mm, the Otus and the 135mm APO Sonnar + An A7r with a ZE55 mounted. 9 times out of 10 the shot I want and the shot I take will be with the Apo Sonnar. I would have never considered a 135mm and was shopping for the 100mm Makro when I bought the 135mm. This is mainly because the Apo makes the most interesting shots that separate themselves from all of the point and shoot focal lengths that numerically dominate the worlds photos. It’s the one lens that never gets in the way of what I am trying to accomplish artistically and with a high res EVF like the A7r I only have myself to blame for a non-keeper.

  • Roger Cicala


    Repeat test variation on the same lens and camera is basically very small, on the order of 1% or so, which is much, much less than inter-sample variation. Mathematical formulas and optic theory say variation comes from very small differences in both element placement and element surfaces. Large variations (i.e. bad copies) are generally from one or two large misplacements of lenses.


  • jintoku

    Roger, may I ask about systematics in the sample variation test? How many times did you test each lens and what was the inter-test variation, i.e., was it significantly smaller than the inter-lens variation?

    Also, what is the prime culprit for sample variation in lenses like these? Does it have to do more with variation in quality of a few lens elements, or more with how a lens was put together?

  • Very appreciate your comment !

  • Roger Cicala

    Hi George,

    I know variations on that story definitely occur. The Sigma 35 Art, I believe, couldn’t use any off-center points on the D800. And Nikon did a firmware update that messed up a several Sigma lenses on several cameras. That’s why I don’t ever recommend a third-party lens for a specific camera unless I’ve shot the combination. It seems there’s always a camera or two that the lenses struggle with until firmware updates, etc. The only good news, I think, is that the dock lets us do those updates at home now, instead of sending them back to Sigma or Tamron, but that’s no help when it’s not working.


  • Hello dear Roger
    Tonns of respect to you and what you do.

    I have a question that regards to Sigmas beauty, it’s no t a question it’s more likely I would love to hear you thought about how Sigma 50mm behave with 1DX bodies.

    After reading all great reviews I’m a bit of hesitant but still curious decided to get one.

    With a great experience with Sigma 35mm F1.4 Art from past wedding season, I really mean great experience – zero adjustments needed 90% hitting rate.

    I was with the idea in my head that finally I’ll get myself not so “nifty” but still “fifty” lensicon wink Sigma 50mm f1 4 dg hsm art

    Started with two copies from authorized Canadian dealer “Vistek” and three copies from “Henrys” and every single one of them was front focusing pretty badly and needed in camera (Auto Focus Micro Adjustment ) AFMA +13 or +17 depends on body.

    Please note we are using few Canon 1dx’s and few 5d mark III camera bodies.

    Even when you micro adjust the lens, the lens was hit and miss in the middle AF points, but the main problem of the Fifty was complete missing on Side AF points.

    I didn’t want to give up and decided to get fifth copy of this lens, as this is really incredible lens … once it nail the focus right.

    Yes it’s heavy, yes it’s huge if you comparing to other fifties around …. but when it hits the focus you just want to cry how sharp the focus areas are and how blurry the out of focus areas, almost like a 85L icon wink Sigma 50mm f1 4 dg hsm art

    So I’ve got this one from “Henry’s” exposure show few days ago, went to a “Sigma” booth there tried with a “Sigma” representative on my two camera bodies and it’s still was front focusing.

    They ask me to bring it to the service, so on Monday morning May 26, 2014 I already been at “Sigma” service Toronto.

    Long story short.

    After 5 days in service, they called me and told that there is nothing to do with this right now and they are waiting for firmware update for this lens.

    They suggested to do in camera AFMA but this for centre AF points only.

    And it looks like Sigma can’t utilize the cross type of far right and far left and simply uses cross type in the center instead of double cross type sensors of 1dx and 5d mark 3 auto focus system.

    Very-very disappointed “Sigma”, I really tried … and it’s really have a great potential to kill the competitors, but right for now it’s going back to the store.

    It is still working when you focusing manual though and it’s still cheaper than Zeiss Otus but it’s very uncomfortable and unreliable when you are working with fast moving objects or happy bride.

    My customers deserve the best !!!

    And I love how someone said about his new Sigma 50mm Art :

    “It’s simply sad, it’s like owning brand new Bugatti Veyron, but only with two wheels, so if you want to move it, you simply have to tow it …”

    Some sample images can be seen here on my blog.

    Thank you

  • John

    Bryan at the Digital Picture has this clearly beating the other Sigma 1.4, very noticeably, and the Canon 1.2 and 1.4, especially open

  • I have waited for quite some time to find a 50mm lens that works well enough for commercial photography. The Sigma 50 Art is remarkable and I have begun to utilize it in my commercial work when the focal length is right for the job. I had little doubt that their Art line would be great since I sold my Canon 300mm f2.8 L IS and replaced it with Sigma’s 120-300 Sport lens. (I rented it first through LensRentals since their association with SuperDigitalCity reimbursed my rental fee with purchase)

    I formerly only used Canon L glass for my work. I’m happy to add the Sigma line to my go to list. Remarkable value and quality.

  • Tom

    Please compare this to the Sony Zeiss 50mm 1.4. In terms of price and the fact that its one of the most expensive mainstream 1.4 lenses out there- many of us are dying to know.

  • Roger Cicala

    Alex, it will be a while. We still don’t have Sony mounts for our new testing equipment.

    However, I did test the ZA 50 a while back and while I found it a nice lens, it isn’t as sharp as the Sigma. On the other hand, I have no idea when the Sigma may actually get released in ZA. We still haven’t gotten any more Canon mounts at all, despite dozens of backordered copies. Nikon is supposed to be out in a month. In some quantity.

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