Verdict

The 40mm f1.4 Art is Sigma’s latest addition to its Art line of high performance large aperture prime lenses designed for full-frame cameras. Originally designed for DSLRs, the lens (and the other prime lenses in the Art line) will soon be available for Sony E-mount (end of March) as well as the L-mount supported by Leica, Panasonic and Sigma. My testing revealed the optical performance of the Sigma 40mm f1.4 Art is near flawless making it one of the best in the Art line: It is very sharp across the full-frame sensor in close quarters and at longer distances, has almost no color aberrations and produces a nice soft Bokeh rendering the background pleasantly blurred. Plus its resistance against flare and glare in strong contra light is very good. Its only optical weakness is the focus shift when stopped down from f1.4 to f2.0. But this is only a problem when using the lens on a DSLR body in phase-detect AF. All modern mirrorless bodies auto-focus stopped down.

So, what’s not to like? Well, the Sigma 40mm f1.4 Art is the biggest and heaviest modern f1.4 lens between the 35mm and 58mm focal lengths on the market: It weighs around 1.2kg in the DSLR version and around 1.3kg in the E-mount and L-mount version. And if you put the lens hood on the total length of the lens is almost 21cm in the E-mount version. That’s humongous!

Let’s put this into perspective and have a closer look at how the Sigma 40mm f1.4 Art compares to some alternatives.

Above from left to right: Sony 35mm f2.8 ZA, Zeiss 40mm f2.0 Batis, Sony 35mm f1.4 ZA, Sigma 40mm f1.4 Art

Compared to Zeiss Batis 40mm f2.0 CF

Ahead of my full review I was able to shoot the Zeiss Batis 40mm f2.0 CF at the same time as the Sigma 40mm f1.4 Art. The Zeiss Batis is similarly priced as the Sigma Art although it only offers a one stop smaller focal ratio of f2.0. But it is much smaller and lighter than the Sigma Art without compromising on build quality or optical performance. Plus it can go down to a much better magnification of almost 1:3 and shoot close-ups in very good quality (thus the moniker “CF”=close focus). Its compact curved design fits snugly on the Sony A7 bodies but that’s it: the lens is currently only available for E-mount and there is no announcement of Zeiss whether the lens will become available for other mirrorless bodies from Nikon, Canon and the L-mount alliance. It also features a unique OLED display, indicating the focusing distance and depth-of-field range at a glance. The main weak point of the Zeiss Batis is its Bokeh: It suffers from the one stop smaller focal ratio and produces very visible onion rings. Not the best preconditions for a creamy Bokeh. But if you value small, light and the ability to get down to 1:3 magnification this is a very interesting alternative.

For more details see my Zeiss Batis 40mm f2.0 CF review where it earned a Highly Recommended.

Compared to Sony FE 35mm f1.4 ZA

The Sony FE 35mm f1.4 ZA is a Zeiss design from 2015 and only available in E-mount. It’s not a small lens either with a total length of 15cm including lens hood, but this is 6cm shorter than the Sigma 40mm f1.4 Art and it weighs only half as much. Optically the Sony ZA is good, but not as good as the Sigma Art: It produces visible color aberrations, is softer towards the corners and has a slightly less creamy Bokeh. The Sony ZA also commands a 20% higher price than the Sigma Art. It offers an aperture ring with 1/3 stop clicks which can be turned off for continuous, smooth, and noise-free operation, but it lacks a display of distance and dof. With its 35mm focal length it captures a slightly wider field of view than the Sigma Art which might be a bonus in tight spaces or when shooting architecture or landscapes. So if size and weight of the Sigma Art is a concern and you value the f1.4 for better light gathering power plus better Bokeh (over an f2.0 lens) the Sony FE 35mm f1.4 ZA might be the right choice.

For more details see my Sony FE 35mm f1.4 ZA review where it earned a recommendation

Compared to Sigma 35mm f1.4 Art

The Sigma 35mm f1.4 Art is an optical design from 2012 and available in mounts for Canon and Nikon DSLRs plus E-mount. In size and weight it’s similar to the Sony 35mm f1.4 ZA and its price of 750 EUR / 900 USD makes it the cheapest of the lenses compared here. Its weak spot is the performance at the border of the APS-C/DX image-circle where residual spherical aberrations and astigmatism mar the otherwise impressive performance even up to f4.0. But otherwise its performance is comparable to the Sony ZA. So the Sigma 35mm f1.4 Art is a very interesting alternative to the Sigma 40mm f1.4 Art delivering a slightly less perfect performance in a smaller and much lighter package with the added bonus of a bit wider field of view – and a lower price.

For more details see my  Sigma 35mm f1.4 Art review.

Sigma 40mm f1.4 Art final verdict

If you can live with the size and weight of this lens, the Sigma 40mm f1.4 Art is a winner: Sharp into the corners of a full-frame sensor, very good resistance against flare, glare and ghosting plus a nice background Bokeh and very low color aberrations and coma. Together with thorough weather-sealing and solid build quality the lens justifies its price and although focus shift can mislead phase-detect AF on DSLRs the Sigma 40mm f1.4 Art clearly earns a Highly Recommended!

Good points:

• Excellent resolution and contrast.
• Very good resistance against flare, glare, and ghosting.
• Very nice background Bokeh.
• Weather sealing.
• Can have the mount changed.
• Versatile customization of AF via USB-dock.

Bad points:

• Size and weight.
• Focus shift (relevant on DSLRs with phase-detect AF).