Sigma 24mm F3.5 DG DN Contemporary

Sigma is addressing photographers who want to use a full-frame camera, but still pack light, with its I Series line of lightweight prime lenses housed in classy aluminum housing. The 24mm F3.5 DG DN Contemporary ($549.99) captures a wide angle of view, focuses close-up, and looks great on your camera. It's a fine lens for mirrorless users, regardless of whether it's an E-Mount or L-Mount system, and an Editors' Choice award winner.

Sigma I Series

Full-frame camera systems are more affordable today than they've ever been, but photographers thinking about moving up from APS-C systems may still be put off by the cost and size of full-frame lenses.

Thankfully, there's been a recent movement toward smaller, affordable (but not cheap) lenses. Sigma puts its small primes in the I Series basket. The 24mm F3.5 covers the widest view of the four primes in the series, which also includes 35mm F2, 45mm F2.8, and 65mm F2 models. They're all available for Sony E-Mount cameras as well as L-Mount models from Leica, Panasonic, and Sigma.

For L-Mount photographers, the lens has few direct competitors. The focal length is covered by zooms, but the only autofocus prime in the vicinity is Leica's $5,200 APO-Summicron-SL 28mm F2 ASPH., one that ticks the premium box, but is neither affordable nor lightweight.

If you use a Sony camera, the lens goes head to head against the company's FE 24mm F2.8 G, a lens that's very similar in concept and execution. Sony's take is also quite light, a little bit smaller, and housed in an aluminum barrel. Neither is quite slim enough to be called a pancake lens—if you don't mind a plastic build, the low-cost Rokinon 24mm F2.8 is there for Sony users who want the smallest, lightest prime around.

Lightweight Wide Angle

The 24mm F3.5 is palm sized, about 1.9 by 2.5 inches (HD). It's small enough to slide into a pocket when not in use (though you'll want to make sure to put the lens cap on first), and a good fit for photographers who like to carry a camera and small shoulder bag. At 7.9 ounces, it's a little heavier than the Sony 24mm F2.8 G (1.8 by 2.7 inches, 5.7 ounces), but just so.

The exterior is aluminum, anodized with a black finish. It looks great and the lens handles well. Sigma puts some space between its focus and aperture control rings, so there's no messing with one while setting the other. You don't get the on-lens function button or silent aperture control that Sony squeezes into its tiny 24mm, though. I don't particularly miss the feature for photography, but if you're more into video, a click-free aperture ring is desirable.

The lens mount is protected with a rubber gasket, giving the lens a modicum of dust and splash protection, but there aren't additional internal seals. You won't have to run for cover if you find yourself enjoying some light precipitation, but this isn't a hurricane-rated lens. If you're an all-weather photographer, the Sony FE 24mm F2.8 G, or Tamron's larger, but budget-friendly 24mm F2.8, are better options.

A metal hood is included, and comes in handy to help keep stray fingerprints and raindrops off of the front glass. The front element is pretty small, but not protected with an anti-smudge coat, so you should be careful with it. You can opt to add a 55mm protective filter, and don't forget to use the lens cap. There are two included—a standard plastic pinch cap and a showy magnetic metal one.

Autofocus is very quick and totally silent, a plus for vloggers after a light, wide lens for walk-and-talk videos. Manual focus is available, too. The focus ring turns comfortably, but with a little bit of resistance. The response is nonlinear, so slower turns make finer adjustments and quicker ones more dramatic.

Videographers may lament the lack of a linear focus response, something you get with the FE 24mm F2.8 G. The Sigma shows noticeably less focus breathing when racking between subjects, though the effect isn't completely absent. You'll still see it when racking from macro to distant subjects, but it's not noticeable with more subtle changes in focus.

Close-up focus is a particular strong point. The lens can autofocus down to 4.3 inches, good enough for 1:2 macro results. Edge clarity isn't the best when focusing close, but results are quite useable, and sharpen if you narrow the f-stop a little bit.

Optical stabilization isn't included, but it's not expected in this type of lens. Most compatible cameras include in-body stabilization. The Sony a7R IV's 5-axis IBIS system is very effective in removing jitters from handheld video, and good enough for blur-free 1/5-second exposures.

The Sigma 24mm F3.5 DG DN Contemporary in the Lab

I tested the 24mm F3.5 DG DN Contemporary in E-Mount and paired it with the 60MP Sony a7R IV and Imatest software to evaluate its optical performance. At its widest aperture, f/3.5, the pair nets very good resolution (3,900 lines). There's a slight drop in clarity at the periphery, but nothing worth fretting over.

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Resolution improves a bit as you stop down, a plus for photographers working with high-end cameras like the a7R IV or the Panasonic S1R. At f/8, it nets excellent resolution from edge to edge (4,600 lines), and continues to shine at f/11.

Photos show a little bit of softness at f/16 and f/22. Diffraction, an unavoidable effect that scatters light particles passing through the very small aperture, is the cause. Landscape photographers may still find it useful, as the lens draws multi-point sunstars at these settings.

At wider apertures, the sun or other bright points of light in your photo aren't as defined. The 7-blade rounded aperture comes into play here. It does a fine job drawing defocused backgrounds, though you'll need to work a bit close to your subject and have some distance between for a real blurred background look.

The optics show some barrel distortion, about 2.4% without correction. In-camera corrections are supported, though, and you should take advantage of them. When they're turned on there's no visible bending of straight lines, making the lens a good fit for architectural work. Corrections also compensate for darkened edges and corners, lessening the vignette effect the lens shows without them.

A Wide Angle for Small Lens Fans

On a whole, the Sigma I Series offers strong value and excellent construction, with optical performance to match. The 24mm F3.5 DG DN Contemporary captures wide views, focuses close, and aluminum construction adds to its appeal.

If you use an L-Mount system, there's no real competition of which to speak—it's the only small, wide prime with autofocus on sale for the system. For Sony owners the waters are a little muddier, but we still like the Sigma enough to make it our Editors' Choice winner.

Its most direct competitor is the Sony FE 24mm F2.8 G, a lens that's a teensy bit smaller and a little more expensive. It's an excellent performer in its own right, and you may prefer its more robust weather protection and silent aperture control ring. We give the Sigma a slight edge, as its controls aren't cramped close together, and we love its fast, quiet autofocus.

At $550, the Sigma 24mm F3.5 falls into a midrange category for price. There are a couple of budget options for Sony owners, too. The Rokinon 24mm isn't as good a performer, but is even slimmer, while the Tamron 24mm F2.8 delivers sharp images, but suffers from slower autofocus. On the other end of the spectrum, the Sony FE 24mm F1.4 GM costs more than twice as much, but is among the best lenses available for any camera system.