Sigma 17-40mm F1.8 DC Art

The Sigma 17-40mm F1.8 DC Art is a standard zoom for APS-C mirrorless cameras with a constant maximum aperture of F1.8. It is available for Sony E, Leica L-Mount, Fujifilm X and Canon RF and covers roughly 25.5 to 60mm in 35mm terms (about 27.2 to 64mm on Canon RF). It suits photographers and video shooters who want a fast zoom for low light and shallow depth of field without swapping primes.

Optical design

Sigma lists 17 elements in 11 groups, including 4 SLD and 4 aspherical elements. According to Sigma, the design concentrates on correcting axial chromatic aberration and sagittal coma flare so that the open F1.8 aperture stays usable. An 11-blade rounded diaphragm and Super Multi-Layer Coating are meant to keep highlights round and reduce flare. The closest focus distance is 28cm, with a maximum magnification of 1:4.8 at 40mm.

Autofocus and handling

An HLA (High-response Linear Actuator) drives the autofocus, which Sigma describes as quiet and fast, and focus breathing is said to be suppressed for video. There is an aperture ring with click and lock switches; the Canon RF version has a control ring instead and no such switches. Two AFL buttons can be assigned functions on supported cameras. The lens has no optical stabilizer, so stabilization has to come from the camera body.

Build and size

An inner zoom keeps the length constant while zooming or focusing. Sigma quotes 525g and 117.9mm for Sony E, 535g and 115.9mm for L-Mount, 530g and 118.2mm for Fujifilm X and 560g and 115.9mm for Canon RF, all with a 72.9mm diameter and a 67mm filter thread. The construction is dust and splash resistant, and the front element has a water and oil repellent coating.

Where it fits

The lens follows the Sigma 18-35mm F1.8 DC HSM Art, built for DSLRs. Sigma says the new lens is over 30% lighter, uses a filter one size smaller and extends the range by 1mm at the wide end and 5mm at the long end. The Sigma 18-50mm F2.8 DC DN Contemporary weighs only 290g but gives up more than a stop of light. For Fujifilm X the Fujifilm XF 16-55mm F2.8 R LM WR II and for Sony E the Sony E 16-55mm F2.8 G are F2.8 alternatives.

Pros and cons

Pros

• Constant F1.8 over the whole zoom range
• Inner zoom with constant length
• Dust and splash resistant, water and oil repellent front coating
• Focusing down to 28cm

Cons

• No built-in stabilization
• Clearly larger and heavier than F2.8 APS-C standard zooms
• The 40mm long end (about 60mm equivalent) is short for tight portraits

Verdict

The Sigma 17-40mm F1.8 DC Art is for APS-C shooters who value maximum light in a zoom and accept a weight of around half a kilogram. It suits low-light photography, video and portraits at the long end, and four mounts make it an option across several systems.