The Sigma 100-400mm F5-6.3 DG DN OS Contemporary ($949) is a built-for-mirrorless telezoom with full-frame coverage, available for E-mount and L-mount camera systems. It offers a bit more reach than 70-300mm, a plus for capturing distant subjects, and a lighter, slimmer build than longer glass like the Sony FE 200-600mm. It's a solid option for naturalists, photographers covering outdoor sports, and others who want more reach than a typical telephoto offers, and can live without the extra magnification power you get from a 600mm zoom.

Editors' Note: This review was updated on 11/19/2020 with new resolution testing data. Our second round of testing was performed with a tripod collar, used to minimize system vibration.

Available for L-Mount and Sony Cameras

You can buy the 100-400mm F5-6.3 DG DN OS Contemporary for E-mount cameras, made by Sony, or for L-mount models from Leica, Panasonic, and Sigma itself. Aside from the lens mount, the two editions are physically identical. Sigma does offer 1.4x and 2.0x teleconverters for the lens in L-mount, but not for Sony cameras.

(Jim Fisher)

It's a sizable zoom—not surprising given its coverage range—measuring 7.8 by 3.4 inches (HD) at its shortest setting. It extends when zooming, just about doubling in length at 400mm, weighs 2.5 pounds, and supports 67mm front filters. A hood is included—it adds a few inches, but goes a long way to protect the front element, and is reversible for storage and transport.

It's in line with other lenses of its type—Sony's FE 100-400mm F4.5-5.6 GM OSS is a bit bigger and heavier all around (8.1 by 3.7 inches, 3.1 pounds), in part because it sports a built-in tripod foot. Sigma doesn't ship one with the 100-400mm Contemporary, but you can buy an add-on collar with an Arca foot for $130—and I recommend doing so if you often use the lens on a tripod or monopod, or use a sling-style camera strap.

(Jim Fisher)

Construction is sturdy. The barrel mixes metal and polycarbonate components, and the materials feel like they're made to stand the test of time. It's not fully weather sealed, though—there's a gasket to prevent dust and moisture from entering at the lens mount, but you don't get the same type of internal sealing as with a Sports series lense from Sigma.

The zoom ring is massive, taking up the front half of the outer, non-extending portion of the barrel. It's finished in rubber, with the typical ridges you see on most zoom controls, and requires about 90 degrees of rotation to move from 100mm to 400mm. There's a lock switch, used to keep the lens set at 100mm, to prevent the zoom creeping out when the lens is hanging at your side.

(Jim Fisher)

There's a manual focus ring too, set farther back and without any sort of rubber covering. The bare polycarbonate ridges turn comfortably, though, with enough drag for precise manual focus. I'd expect photographers to rely on autofocus most of the time—it's quick, quiet, and accurate (when tested with a Sony a7R IV). An on-lens toggle switches focus modes directly, so you don't have to fiddle with camera menus.

Other on-lens controls include a focus limiter—to swap between the full range, close subjects only, or distant subjects only—as well as a switch to control the stabilization system and an assignable control button—on my a7R IV, I had it set to engage autofocus tracking.

(Jim Fisher)

The stabilization system has two modes—one for use when your camera is still, and a second to use when panning along with moving subjects. With the a7R IV, I netted consistently blur-free results at 1/15-second when zoomed to 400mm.

You can get fairly close-up shots, but the lens is a bit shy of a macro. It can focus to 3.6 feet (1.1 meter), good enough for 1:4.2 life-size magnification. You can certainly get some detail shots from the hiking trail, but you'll need to pay attention to the zoom setting—the close-up capability is only good through about 350mm, beyond that focus is limited to 6.6 feet (2 meters) and farther. It's a bit contrarian to think that zooming out a bit will net greater magnification, but it's the case with this lens.

In the Lab

I tested the 100-400mm Contemporary along with the 60MP Sony a7R IV, currently the company's highest-resolution model, and software from Imatest.

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(Jim Fisher)

The lens nets resolution considered very good for the a7R IV at 100mm f/5 (4,100 lines), and stays in that range all the way through f/16. You can narrow to f/22 (and smaller settings when zoomed in), but it does serious harm to image quality—I'd avoid using the lens at its smallest f-stops at any focal length.

Resolution is excellent at 200mm (4,700 lines), even at the wide-open f/5.6 aperture, and remains so through f/11. Results are still very good at f/16, but fall off with the diaphragm set tighter—you can go as narrow as f/25 at 200mm.

(Jim Fisher)

See How We Test Cameras and Lenses

There's a measured drop in resolution at 300mm, but results remain solidly good at f/6.3 (3,450 lines) and are crisper when stopped down to f/8 (3,650 lines), with quality results through f/16. You can stop down as far as f/29, but diffraction really cuts into clarity at very narrow f-stops.

Results at 400mm are right in line. At f/6.3 we see good performance (3,200 lines), and it ticks up a bit at f/8 and f/11 (3,450 lines). If you're using a high-resolution Sony body, think about spending for the Sony FE 100-400mm F4.5-5.6 GM OSS—it netted excellent results when tested with the 42MP a7R III, and supports teleconverters to extend its reach, something Sigma doesn't offer for the E-mount version of this lens.

If you're using an a9 or a 24MP a7 model, though, it'll be harder to spot the difference between the two lenses.

(Jim Fisher)

For photographers with L-mount systems, the 100-400mm should pair quite well with the Panasonic S5 or S1. There's not yet a Sigma Sports-level telezoom to match the higher resolution sensors found in the Panasonic S1R and Leica SL2.

In-camera corrections curb distortion and vignetting when capturing photos in JPG format. Processed Raw photos show a bit of pincushion distortion, typical of a telezoom, and a modest vignette when using the lens at its maximum aperture. Adobe Lightroom supports one-click distortion and vignette correction for this lens.

A True Midrange Option

The Sigma 100-400mm F5-6.3 DG DN OS Contemporary sits in the middle of the pack of telezooms in reach—there are others that only stretch to 200mm, and those that go as far as 600mm—and costs a bit more than budget alternatives like the $549 Tamron 70-300mm f/4.5-6.3 Di III RXD.

(Jim Fisher)

For around $949, the 100-400mm offers a lot of value. Sony owners can compare it with the $2,500 FE 100-400mm GM, a lens that's a bit better built and supports teleconverters—Sigma doesn't offer them for the Sony version of the lens—but if you don't need the extra reach, and don't use a high-end 60MP camera, spending less has plenty of appeal.

For L-mount owners there are fewer viable alternatives. Panasonic has a pair of 70-200mm zooms, one F4 and one F2.8, and Leica sells a $7,000 90-280mm, making the 100-400mm the clear telephoto choice for now. Teleconverters are available for L cameras too, giving you the option to extend reach to 600mm or 800mm. It's not a bright lens to begin with, though, so you'll absolutely want to work in bright, ample light to get the best results when using a teleconverter.

(Jim Fisher)

Regardless of your camera system, the 100-400mm Contemporary is a lens to look at if you're shopping for a zoom and want one that gets closer than a 70-300mm. There's a lot of value here, in a package that's lighter and easier to carry than alternatives like the Sony FE 200-600mm.