Sigma has announced a set of three new primes for full-frame mirrorless cameras, to be available in E and L mounts. These 24mm F3.5, 35mm F2 and 65mm F2 optics share features and design philosophy with the existing firm’s 45mm F2.8 DG DN, with which they now form a new ‘I series’ of lenses. They’re designed to be compact, provide excellent build quality with a metal housing, and deliver superb image quality on a par with the firm’s highly regarded Art-series optics.

Sigma I series 24mm F3.5 DG DN | Contemporary

First up, the Sigma I series 24mm F3.5 DG DN | Contemporary is a compact wideangle prime that measures 64mm in diameter and 48.8mm in length, while weighing 225g. It employs 10 elements in 8 groups, including one SLD element and three aspherical elements to suppress optical aberrations. A stepping motor is used for autofocus, with an impressive minimum focus distance of just 10.8cm providing half life-size magnification. The lens accepts 55mm filters and comes with a petal-type hood. It will cost £479.99 and go on sale slightly later than its siblings, on 22 Jan 2021.

Sigma I series 35mm F2 DG DN | Contemporary with hood attached

Secondly, the Sigma I series 35mm F2 DG DN | Contemporary is designed to be an everyday walkaround lens. Like the 24mm it doesn’t skimp on glass, with 10 elements in 9 groups, including one SLD element and three aspherical elements. It’s a little larger at 70mm diameter by 65mm length, while weighing 325g. It employs 58mm filters and can focus as close as 27cm. The 35mm f2 will cost £549.99, and go on sale 1 Jan 2021.

Sigma I series 65mm F2 DG DN | Contemporary

Last but not least is the Sigma I series 65mm F2 DG DN | Contemporary. Not surprisingly it’s the largest of the three, at 74.7mm long and 72mm in diameter, while tipping the scales at 405g. It’ll focus down to 55cm, and takes 62mm filters. Optically, there are 12 elements in 9 groups, with one SLD element and two aspherical elements. This lens will cost £649.99 and is scheduled to go on sale 1 Jan 2021.

All three lenses share a similar design and layout, with the manual focus ring at the front, and an aperture ring closer to the camera body. This clicks at one-third stop increments, and has an A position that passes control back to a dial on the camera. In addition, both the 35mm F2 and 65mm F2 sport a large arc-shaped AF-MF switch. The lenses aren’t specifically claimed to be weather-sealed, but do have an O-ring around the mount to help stop dust or water getting into the camera.

The new Sigma 24mm F3.5 mounted on a Sony Alpha 7-series body

Each lens is also provided with a metal lens hood in the box. There’s also a magnetic metal lens cap that clips directly onto the front of the lens, along with a conventional plastic cap. The firm is even producing an optional holder that the metal cap will attach to magnetically.