Lenses

Sigma 45mm f/2.8 DGDN Mini-Review – By JK Lockwood

May 1, 2020

Sigma introduced the 45mm f/2.8 DG DN lens last year for Sony E-mount and Leica L-mount cameras. It is part of their Contemporary line of lenses. Sigma had four goals when designing this lens: small size, high optical performance, a short minimum focus distance, and exceptional build quality. I believe they succeeded on all counts and deliver excellent image quality and performance in a very compact AF prime lens. Let’s look at how they managed all of these goals to produce a uniquely modern lens with classic rendering.

SIGMA 45mm DG DN @ f/2.8

Background

It all started when I purchased a Leica SL (Typ 601). My goal was to utilize small M-mount lenses (that I already owned) on a more modern, digital platform than my Leica M4-P film camera. Reports were that the Leica SL excelled with M glass, with the added benefit of focus aids like peaking and zoom. All was going well with the camera and my manual-focus lenses, but I felt like I might be missing out on some of the capabilities of this modern mirrorless marvel. So along came the most compact L-Mount prime I could find, the Sigma 45mm f/2.8 DG DN.

SIGMA 45mm DG DN @ f/2.8

Why 45mm and Why f/2.8?

For street and walk-around use, the 45mm focal length is marvelous, fitting right between classic 50mm and 35mm lenses. It is as close to the measured diagonal of our 35mm-shaped frame as one can get. Considered a “normal lens”, it doesn’t impose an opinion on our images, it just looks natural. It doesn’t compress like a telephoto lens, nor exaggerate like a wide-angle. Because of this, creating visually compelling images is incumbent on the photographer.

As for its relative lack of speed at f/2.8, I answer two-fold: The modern EVF cameras this lens is designed for already have a bright viewfinder experience. Gone are the days of needing a faster lens to create a brighter image to facilitate manual focusing. Also, without film’s fixed-ISO, f/2.8 is rarely a problem. Photojournalists live and die by their f/2.8 zooms, as did I for many years shooting social and corporate events. So, plenty fast and practical for me.

SIGMA 45mm DG DN @ f/5.6

Sharpness

A frequent complaint about this lens is a lack of sharpness at f/2.8. According to Sigma, design emphasis was placed on producing “exceptionally beautiful bokeh” over wide-open sharpness. Stopping down to f/5.6 reportedly yields sharpness and contrast equal to their Art lens line. Focus on the image below, shot wide-open, was on the trolley sign:

SIGMA 45mm DG DN @ f/2.8

Another “fault” of the lens (related to sharpness) is noticeable as a veiling haze when the lens is shot wide-open and focused closely. Note the “glow” of the street sign below and prominent vignetting. This haze disappears as one stops down and sharpness improves greatly. I tend to think of this as a feature to be harnessed, especially in portraiture. Sigma goes into great detail explaining how they harnessed spherical aberrations in this fascinating behind-the-scenes article explaining the lens design process, https://www.sigma-sein.com/en/ohsone/45mm-f2-8-dg-dn-contemporary/

Full frame vs. crop shot at f/2.8

Pixel Peeping

Admittedly, I’m not normally a pixel-peeper or an optical expert. I rarely dissect lens performance by scrolling around at 100% on a color-corrected monitor. Nor do I pay any attention to MTF charts. But this once, I thought it might be interesting to proceed a little more scientifically and compare the Sigma with adapted Zeiss and Leica M lenses that I already owned.

The following images were taken from a tripod at approximately 3 meters, wide-open, focusing on the speed limit sign. I compared the Sigma 45mm, with a Zeiss Planar 50mm f/2 ZM and a Leica Summarit-M 35mm f/2.5 with some surprising results. Since these lenses offer similar angles of view and could be used interchangeably, I felt a direct comparison might prove beneficial.


Sigma 45mm at f/2.8 full-frame vs. crop


Zeiss 50MM at f/2 full-frame vs. crop


Leica 35MM Summarit-M at f/2.5 full-frame vs. crop

Indeed the above images show an interesting comparison between these modern lenses. I initially picked up a “busyness” in the leaves in the upper left corner and circular bokeh (sphero-chromatic aberration) to the right of the sign. It was especially pronounced with the Leica and Zeiss lenses, but not the Sigma. The 45mm DG DN simply renders a smooth, natural bokeh, the sort produced by the Zeiss glass I used with my Hasselblad V Series cameras.

SIGMA 45mm DG DN @ f/2.8

SIGMA 45mm DG DN @ f/2.8

Conclusion

To my eye, the Sigma 45mm f/2.8 DG DN lens offers a unique, classical rendering. Its inherent close-up softness is actually a benefit for portrait subjects and could be utilized to soften skin texture in both still and video images. Overall, the AF is quick, with close-focusing capability far greater than any rangefinder lens. The build quality is also beyond reproach, with an all-metal body and weather-sealing. The size is perfect on both my Leica SL and Leica CL cameras. I hope Sigma continues down the path of offering small autofocus prime lenses like this modern-day classic.

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14 Comments

  • Reply
    Khürt Louis Williams
    May 1, 2020 at 12:26 pm

    I don’t own a Leica, but I wanted to comment that this was one of the most pleasant mini-reviews I have read on 35mmc. Thank you for including interesting colour photographs of people and places.

    I agree with everything you wrote in the “Why 45mm f/2.8?” section. In my opinion, the 40-45mm focal range is perfect for the street photographer as that is within the normal field of view of human vision.

    • Reply
      JK Lockwood
      May 1, 2020 at 4:20 pm

      Thank you for the kind words. I’m glad you enjoyed the review!

  • Reply
    Huss
    May 1, 2020 at 8:23 pm

    The Zeiss Planar seems sharper and has nicer bokeh.
    It is smaller, faster and cheaper. But no AF.

    Thanks for the test!

    • Reply
      JK Lockwood
      May 2, 2020 at 2:13 am

      The 50mm Zeiss ZM has a current price of $903 USD, the Sigma is $549, and was $499 when I picked it up.

      • Reply
        Huss
        May 3, 2020 at 5:47 pm

        Ahh, did not realize the Sigma was much cheaper. I picked up my Zeiss for $550 used like new, then again you could also get the Sigma cheaper used.
        Do you actually prefer the Sigma to your Zeiss seeing you have both? AF is handy but the SL2 is very easy to focus manually.

        • Reply
          JK Lockwood
          May 3, 2020 at 9:09 pm

          The Zeiss and Leica M lenses were already in my stable, in use with my Leica M4-P. The color and contrast of Zeiss lenses are a favorite. Purchasing the SL Type 601 was, for me, a way to obtain a digital Leica platform, inexpensively.

          The compact size and IQ one can get from M lenses on FF 35mm is truly amazing. They really are a marvel compared to the modern (bloated) AF lenses that produce the same size image circle. The Sigma is the only choice if one wants a moderately sized AF lens for the L-mount.

  • Reply
    Marc Wick
    May 2, 2020 at 5:13 pm

    A very good review, not so dry but very informative. I think that Sigma lenses also are a very good option for the SL user. Especially the zooms will be not as huge as the Leica zooms. The Sigma 2.8/45 looks good on the SL and is very tiny in comparison the the 50 or 35 version from Leica.

    • Reply
      JK Lockwood
      May 3, 2020 at 4:17 pm

      Thank you, glad you enjoyed the review. Compact size mas my main reason for choosing this over their other L-mount options. Hope there will be more!

  • Reply
    Scott Mackie
    May 3, 2020 at 2:42 am

    Really enjoyed this review. Caught my interest as I just picked up a used Sigma 45mm to play with on my CL. It’s a really nice complement to the CL – not too big and a bit lighter than the 35mm Summilux-TL.

    The link to the Sigma article was *really* helpful tho. I hadn’t fully got the old-school lens aspects of this so when I shot it wide open last week I was pretty surprised. Once I’d gotten over the fact that it looked like a mid-50s LTM on an adapter when focussed close and wide open, I started to get into it. If you get close to the minimal focus distance, there really is a nice ethereal quality to the image. It doesn’t look forced tho – more organic, which is obviously the design intent. The effect pretty much disappears if you step down to f/4.0 or back off of the focus point.

    On the CL, it’s more like a slightly short portrait lens because of the APC-C sensor so it’s an interesting combination. Don’t really do a lot of portrait work but might be tempted given what I’ve seen.

    • Reply
      JK Lockwood
      May 3, 2020 at 4:14 pm

      The Sigma should be a stellar lens on your CL. Glad you enjoyed the review. You clearly “get it”!

  • Reply
    jh
    May 3, 2020 at 7:15 am

    I own the Sigma Fp & had a choice of this lens, the Rokkor 40/2 & Voightlander 40/1.4. In the end I went with the Rokkor as it’s compact size was my main reason & it is super sharp. Bokeh is not as smooth (similar to the Summarit), but for a street pocket rocket I’m glad I went this direction. (I also own the Voight 25/4 CS & Voight 75/2.5 CS) All these lenses can fit in my pocket and have a full range. However I hear Sigma will be bringing similar ‘small’ lenses https://www.dpreview.com/interviews/2134621161/sigma-interview-smaller-high-quality-lenses-coming-in-the-near-future This will be interesting, as will see how they compare to the compactness and rendering of the x3 compact lenses I have. Thx for the review

    • Reply
      JK Lockwood
      May 3, 2020 at 9:42 pm

      You are very welcome JH. Glad we can discuss and share our passion for image making and I’m thankful for the 35mmc community!

  • Reply
    Chris Nebard
    April 19, 2022 at 7:48 pm

    I know that this review is a couple of years old now but it helped me to choose the Sigma 45 as the first prime for my SL2-S (last August 2021). Some months on, it’s had a great deal of use and everything you mention is absolutely right. In fact, for me, the small size of this lovely lens completely transforms SL cameras and makes them much more usable for street, travel and generally just carrying around. The performance of these Sigma Contemporary I series prime lenses is, I think, very good indeed. That “softness” on the 45 at f2.8 (which is not shared by the others as far as I can see) is only prevalent at very close focus – it disappears if I shoot a few feet from my subject – and (again, as you point out) it can be a lovely feature and is to be taken advantage of. Since reading this review & buying the 45, I’ve also bought the 24 f3.5 and the 35 f2. Both are superb but my fondness for the little 45mm remains. It will, in time, become a modern classic. Its rendering is already there.
    Thank you.
    Chris

    • Reply
      JK Lockwood
      April 19, 2022 at 8:06 pm

      Thanks for the kind words Chris. I’m glad my thoughts were helpful. As you state, I keep coming back to the 45 on my SL. I also, subsequently bought the same two additional optics 😉

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