Lens review

Sigma A 40 mm f/1.4 DG HSM

10 December 2018
Arkadiusz Olech

11. Summary


  • solid, stylish casing,
  • sensational image quality in the frame centre,
  • brillant image quality on the edge of the APS-C sensor,
  • fantastic image quality on the edge of full frame,
  • lack of chromatic aberration problems,
  • negligible lateral chromatic aberration,
  • imperceptible distortion,
  • excellent coma correction,
  • slight astigmatism,
  • low vignetting on the APS-C/DX sensor,
  • nice out-of-focus areas,
  • noiseless autofocus.


  • some problems with spherical aberration,
  • high level of vignetting at the maximum relative aperture on full frame,
  • significant physical dimensions and big weight.
I have no doubts that the Sigma A 40 mm f/1.4 DG HSM is a show of force of that Japanese producer. Having in their line-up such models as the 35 and the 50 mm they could focus on filling gaps in 135 – 500 mm focal range. Still they decided to follow another path and showed a wide angle optical instrument which provides sensational images already by f/1.4 across the frame and its image quality even on the very edge of the frame can put to shame cult lenses of other renowned manufacturers.

Was such a show of force indispensable? I admit there are some problems with answering that question unanimously. There is no doubt Sigma have proved time and again that they are perfectly able to produce excellent lenses. The era when they could be treated as a ‘second best’ third part optics manufacturer, known for cheaper, weaker substitutes of brand name products, belongs to the past. Small wonder that, without size or weight limits, their team of exceptionally gifted optics specialists constructed an outstanding optical device in every respect. Was it worth the effort? Some might answer ‘yes’ because e.g. in astrophotography the perfect image quality across the frame and coma-free shots by f/1.4 are simply priceless. Significant weight and dimensions of the lens are of secondary importance because even small equatorial mounts allows the lens to stay fixed on any celestial object by driving one axis at a constant speed. Still, when it comes to more ‘earthly’ usages I admit you can shot equally good photos with the Sigma 1.4/35 of the Sigma 1.4/50. From that point of view the 40 mm model is just a curiosity; its superior image quality is not worth spending more money and carrying those additional hundreds of grams around your neck or in your bag.

As we’ve already mentioned money – the tested Sigma A 1.4/40 costs almost $1400 so $450-$500 more than the Art line 1.4/35 and 1.4/50 devices. Still you can hardly call that price exuberant; the Zeiss Batis 2/40, by 1 EV slower and definitely not as optically complex, has a similar price tag, that of almost $1300.

Please Support Us

If you enjoy our reviews and articles, and you want us to continue our work please, support our website by donating through PayPal. The funds are going to be used for paying our editorial team, renting servers, and equipping our testing studio; only that way we will be able to continue providing you interesting content for free.

- - - - - - - - - - - - - - - - - advertisement - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

I suppose the term ‘the last samurai’ suits Sigma the best – that company is perhaps the last of big players on the market following a managing model so far removed from the corporate one. They still produce lenses in one plant located in Japan; it’s been the same place for several dozen years. I suppose their production output is limited to some extent. If the launch and production of the Sigma A 40 mm f/1.4 DG HSM influences the number of other novelties and limits the availability of other models in the line-up I will consider this idea a bit pointless. On the other hand I am in no position to lecture Sigma managers on what models they should produce and launch. I am just a modest tester from a country which launched its own original lenses over 30 years ago so I don’t feel qualified to argue or advise anybody what to do or what not to do. I think we should assume the Sigma management know what they are doing. Let’s simply enjoy another optical gem and a truly sensational lens produced by that company.