The 18-35 ART has Sigma’s increasingly familiar (yet still excellent) new design ethos. The two shots below give you an idea of how that zoom range looks like in real life: On a Nikon, Sony, Pentax, or Sigma body the crop factor is 1.5x and the lens will have an equivalent focal length of 27-52.5mm. Canon (reviewed here) has a 1.6x crop factor. The focal length equivalency will depend on what system you are using and its crop factor. The 18-35mm has a full frame (35mm) equivalent focal length of 28.8-56mm (on a Canon). The success of this lens has allowed Sigma to greenlight a somewhat similar full frame lens, although that lens (a 24-35mm f/2) has a smaller zoom range, a slightly smaller aperture, and is a bit heavier (+130g). So no, this lens doesn’t really work on a full frame body (more on that a little later). Sigma hedged its bets with this somewhat radical design by using a fairly small zoom range and designing a crop sensor only (APS-C) lens. The same would be true for the more robust bodies from any of the camera systems that this lens is sold for (Canon, Nikon, Sony, Pentax, and Sigma). It might feel a bit front heavy on smaller consumer DSLRs, but balanced nicely on my “prosumer” 70D. This lens is a bit longer but narrower than most 24-70mm designs.

Its specs are almost identical to those of Canon 24-70mm f/2.8L II (the Sigma is 8mm longer and 5 grams heavier). It is slightly longer than Sigma’s own 24-70mm f/2.8 (4.76” vs. The 18-35ART isn’t small or light, but neither is it exceptionally large or unwieldy. It has been an unspoken rule of sorts that zoom lenses generally have a maximum aperture of f/2.8 (I currently own three that follow this “rule”), and the understanding was that the physics of building a zoom lens with a larger aperture than f/2.8 would produce a lens larger, heavier, and more expensive than photographers would be willing to bear. Yes, that isn’t a typo! This is a zoom lens with a constant maximum aperture of f/1.8, making it a completely unique lens in the current market. That is definitely true of the lens being reviewed here, the Sigma 18-35mm f/1.8 DC HSM ART lens. But Sigma has also demonstrated the ability to think outside of the box and take a few chances. I have now reviewed lenses from all three categories of Sigma’s Global Strategy (Art, Sport, and Contemporary), and despite still not having a clue what “Contemporary” is supposed to mean in this context, I can attest that the cosmetic design and general construction of all of these lenses is excellent. Sigma lenses still have their quirks (more on that in a moment), but they are building the handsomest lenses on the market. Whoever came up with their new “Global Vision” marketing strategy deserves a raise, and the team that came up with their new design ethos deserves an even bigger one. Clearly a decision was made to target a more premium place in the market, and so they scrapped their existing design philosophy entirely along with their marketing strategy. A few years ago they awoke from their third party slumber and realized that they were capable of making better products than what they were currently building.

Sigma 18 35 1.8 mtf chart