Introduction

The Sigma 24mm F2 DG DN C and Sigma 90mm F2.8 DG DN C are the latest additions to the company’s I series of compact, mid-paced primes.

The ‘C’ indicates that they’re part of Sigma’s ‘Contemporary’ range, which offers a more accessible balance between price, size and performance.

The DN part of the name signifies that these lenses are ‘digital native’ designs, which is Sigma’s term for lenses designed from scratch for mirrorless cameras. Initially, both lenses will be available for Sony’s E mount and the L mount used by the L-mount Alliance made up of Sigma, Panasonic and Leica.

Sigma 24mm F2 vs 24mm F3.5

The 24mm F2 DG DN C (shown here) arrives as a larger, faster alternative to the existing 24mm F3.5 DG DN C. It uses a much more complex optical formula, with 13 elements in 10 groups, including one ‘fluorite-like’ FLD element, two super-low dispersion SLD elements and two aspherics. In comparison, the existing F3.5 lens has 10 elements in 9 groups, with only one SLD element and one aspherical element.

Sigma 24mm F2 DG DN | C

The faster lens has a longer minimum focus distance, producing a 1:6.7 magnification ratio at 24.5mm (9.7″), rather than the 1:2 ratio of the 24mm F3.5. In return, Sigma promises ‘the highest level of optical performance’ all the way up to F2, and says sagittal flare, or coma, has been minimized. This makes it ideal for astrophotography, whereas the existing lens prioritized size and bokeh rendering.

Sigma 24mm F2 DG DN | C

The 24mm F2 features the standard all-metal construction shared by all the I series primes, and it comes with a metal petal-style hood.

The metal construction, along with the wide aperture and complex design make the 24mm F2 the second-heaviest lens in the series, at 365g (12.9oz), as well as the second-longest, at 72mm (2.8″) long for the L-mount version.

Controls and build

Despite being one of the bigger lenses in the series the 24mm F2 is still usefully compact, even when mounted on one of Sigma’s diminutive fp models. There’s still plenty of room on the body for a decently wide focus ring and a narrower, stepped aperture ring. Just behind this is a fairly substantial MF/AF switch set in a recess that’s painted on the MF side, so you can see its status at a glance.

The aperture ring has an ‘A’ position on it, if you want to pass aperture control off to the camera body, and the back of the lens features a rubber gasket to prevent moisture ingress. It comes with both a plastic pinch-style lens cap and a metal cap that attaches magnetically.

The high quality construction contributes towards a list price of $639, putting it in the midrange price bracket of modern AF lenses for full-frame systems.

Sigma 90mm F2.8 DG DN | C

The 90mm F2.8 DG DN C has the longest focal length in the I series so far, with an angle of view that makes it ideally suited to portraiture.

It features 11 elements in 10 groups, including five special low dispersion (SLD) elements and one aspherical lens. Sigma says the design should minimize longitudinal chromatic aberrations (LoCA), the purple and green fringing in out-of-focus areas that can be awkward to correct. It also says the design should live up to the demands of the latest high-res camera bodies.

90mm

The 90mm F2.8 DG DN | C is relatively small, at just 60mm (2.4″) long and 64mm (2.5″) wide. Adding the included metal hood extends the lens’ length to 100mm (3.9″). Despite its all-metal construction, the 90mm lens weighs a pretty reasonable 295g (10.4oz).

The 90mm F2.8 shares its 55mm filter diameter with the 24mm F3.5 and 45mm F2.8, suggesting the three comparatively small I series lenses are intended as something of a set.

Aperture ring

Like the other I Series lenses it features all metal construction and features a clicking aperture ring, with an ‘A’ position some distance beyond its F22 setting, to allow control of the aperture value from the camera body, but without risk of accidental engagement.

Sigma doesn’t provide an option to de-click the aperture ring for video shooters but videographers may be interested to note that focus breathing (a change in angle of view as you focus) is very well controlled on the 90mm F2. The same is not true for the 24mm F2.

Construction and controls

In terms of other controls there’s a broad, textured focus ring with a smooth, well-damped feel to its operation, and an AF/MF switch painted so you can clearly see which setting it’s in.

Speaking of focus, both lenses focus swiftly and quietly, despite employing stepper motors, which tend to be slightly slower than their linear motor counterparts.

There’s a rubber gasket at the back of the lens, to help maintain a moisture and dust resistant seal with the camera. Like the 24mm F2, the 90mm F2.8 will sell for a recommended price of $639.

Summary

The 24mm F2 and 90mm F2.8 become the fifth and sixth addition to Sigma’s I Series of relatively compact, high quality but affordable prime lenses.

The latest options join the existing 24mm F3.5, 35mm F2, 45mm F2.8 and 60mm F2 in the I series lineup, meaning there’s now a choice of compact, semi-fast primes stretching from wideangle to short telephoto. This gives E and L-mount users the chance to select their favored focal lengths to build towards kits that help keep the overall size of their system down.

And, if Sigma’s history and public statements are anything to go by, the range may one day be available for other full-frame mirrorless systems.

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