Field Test: Sigma 14mm f/1.8 + 24-70mm f/2.8 ART Lenses
If you're into wider-aperture wide-angle lenses that deliver ridiculously sharp image files (as I am) you're precisely the person Sigma had in its crosshairs when the company whipped up its latest high-performance hotties-the Sigma 14mm f/1.8 DG HSM ART and Sigma 24-70mm f/2.8 DG OS HSM ART -series lenses.
Photographs © Allan Weitz, 2017
As with all Sigma ART-series lenses, the new lenses are designed to go up against the best glass that Canon, Nikon, Sony, Pentax, and other camera and lens manufacturers offer. These lenses are built well and they deliver sharp detail with excellent contrast and aberration control across the viewing field. And yes, Sigma's been doing an excellent job in all respects.
Sigma ART-series lens barrels are made from metal alloy with external moving parts manufactured from "thermally stable composite material" (TSC), which is lightweight and resists thermal expansion and contraction. The lens mounts are made of brass, and the lenses are sealed to be dust- and splash-proof. As a tactile experience, Sigma's ART-series lenses feel reassuringly solid and built for life on the road.
Both lenses contain a combination of ELD (Extraordinary Low Dispersion), SLD (Special Low Dispersion), and FLD ("F" Low Dispersion) lens elements, which together create extremely sharp, near distortion-free and aberration-free image files.
To keep flare and ghosting to a minimum, even when shooting directly into the sun or similarly bright light sources, Sigma Super Multi-Layer Coatings are employed on all lens surfaces. How does all this work in real life? Based on the pictures I captured with them, very well, thank you.
Though most people interpret the term "good bokeh" as meaning "shallow focus," the traditional interpretation of the Japanese expression describes the characteristics of the out-of-focus highlights of a photograph. If the blurred specular highlights in the background and foreground are circular with gently feathered edges, which is the way the pupils in our eyes interpret them, it's "good bokeh." If they appear angular and/or jagged this is what's described as "nervous bokeh," which, as the name implies, is not as satisfying to our visual senses. For the record, the bokeh signature of both of these new Sigma ART-series lenses is quite nice.
Both lenses are available in three lens mounts: Nikon F, Canon EF, and Sigma SA. At this point in time, there isn't a Sony E-mount version of either of these lenses. In its stead, Sigma packages the Canon EF version of the lens and a Sigma MC-11 Canon EF-Sony E-mount adapter-the combination I used for this lens review.
From experience, I already knew the MC-11 adapter reduces the autofocus speed of the host lens. The response times are adequate, but I wouldn't recommend this arrangement for sports or other fast-action imaging. According to Sigma, the autofocus response times of lenses with dedicated lens mounts (Canon EF, Nikon F, and Sigma SA) are notably quicker than the Sony version of these lenses. Not having used any of the dedicated version, we'll have to take Sigma's word for it.
Something I had trouble getting used to with both lenses was the location, width, and texture of the focus and zoom rings. Perhaps I might feel more familiar with them over time but, out of the box, I found myself breaking concentration in search of the ring more often than I'd prefer.
The Nikon version of both lenses incorporates electromagnetic diaphragm mechanisms similar to the mechanisms found in Nikon OEM lenses.
Sigma 14mm f/1.8 DG HSM ART Lens
It's hard not to notice the size of Sigma's fastest-in-it- class ultra-wide ART lens. Though physically about the same size as the 14mm f/2.8 alternatives from Canon, Sony, Rokinon, etc., the 1.33 stop advantage of the new Sigma lens adds more than a pound of additional weight, compared to the competition.
Having owned many large, heavy lenses over the years, I've grown to appreciate the plus sides of smaller, lighter camera gear. Personal appreciation for smaller and lighter gear aside, I quickly learned to appreciate the fine degree of sharp, selective focusing Sigma's 14mm f/1.8 DG HSM ART lens afforded me.
The pictures this lens captures at f/1.8 are unlike anything I can possibly capture with a Voigtlander Super Wide-Heliar 15mm f/4.5 ultra-wide-a much smaller, lighter, and notably slower wide-angle lens I own and adore. What's sharp in images captured with Sigma's 14mm f/1.8 lens is very sharp, while everything in front of and behind the points of focus feather off to a most pleasing form of bokeh. Conversely, when stopped down to f/11 and smaller the depth-of-field seemingly goes on forever.
Unlike earlier-generation ultra-wide-angle lenses, these two lenses display little, if any, vignetting, color smearing, or other image-degrading attributes, especially toward the corners of the frame. From the earliest days of wide-angle photography, vignetting has been an issue. This no longer seems to be the case.
The Canon EF, Nikon F, and Sigma SA versions of this lens feature dedicated lens mounts. The Sony E mount version of this lens consists of the Canon EF version of the lens bundled with a Sigma MC-11 Canon EF-Sony E Lens Adapter, as I wrote above. If you go this route, make sure your MC-11 lens adapter is running on the latest firmware for optimal performance. Firmware updates are downloadable on the Sigma website.
A switch on the side of the lens barrel allows you to switch quickly between autofocus and manual focus with the flip of a side-mounted AF/M tab.
In a bid to optimize image quality by reducing chromatic aberrations and delivering sharp, evenly lit, corner-to-corner image quality, Sigma's 14mm f/1.8 DG HSM contains three FLD elements, four SLD elements, and a large 80mm precision-molded glass aspherical front lens element that practically jumps out at you.
Surprisingly, there was little in the way of obvious flare due to direct sun or bright specular light sources.
If you own a Sigma 14mm f/1.8 DG HSM, you're inevitably going to want to use it on a tripod-mounted camera. Be warned: this lens is heavy and has a center of gravity that protrudes far from the lens mount. (A rotating lens collar would have been a nice touch.) To avoid damaging the baseplate of your camera, I suggest using a Benro LB200 Arca-Type Lens Bracket, Really Right Stuff Long Lens Y-Support Package with Dual QR Clamps, or similar lens support bracket between your camera and tripod head.
Sigma 24-70mm f/2.8 DG OS HSM ART
There's a reason 24-70mm f/2.8 zoom lenses are available from virtually every camera and lens manufacturer. They're wide enough for shooting landscapes, architecture, and group portraits in tight quarters and long enough to capture flattering headshots. Street shooters love them. So do wedding photographers and an untold number of photo enthusiasts.
The Sigma 24-70mm f/2.8 DG OS HSM ART, which has an AoV range of 84.1 to 34.3, focuses down to 1.21', accepts 82mm filters, and weighs 2.24 lb. It's available in dedicated mounts for Canon EF, Nikon F, and Sigma SA cameras. As with the Sigma 14mm f/1.8 DG HSM, the Sony E mount version of this lens consists of a Canon EF version bundled with a Sigma MC-11 Canon EF-Sony E Lens Adapter.
When shooting in low light, you have the option of switching on the lens's optical stabilization system, which, according to Sigma, provides a four-stop advantage.
Overall, I found this lens to be an excellent performer across its entire focal range, both wide-open and stopped-down to smaller apertures. At wider apertures, there's a nice separation between the sharper and blurrier portions of the frame, with rich color saturation. Despite its size, the lens balances well on a Sony A7R II, and would make for a productive one-lens solution for day tripping, travel, and almost any other genre of photography.
The Sigma 24-70mm f/2.8 ART has similar specs (weight, length, and width) as its faster and wider 14mm sibling. If, as with the 14mm lens, you plan on using this lens on a tripod-mounted camera, consider adding a lens support between your camera and tripod head to reduce stress on the camera mount. Recommendations include the Benro LB200 Arca-Type Lens Bracket and Really Right Stuff Long Lens Y-Support Package with Dual QR Clamps.
Do you have any experiences with wider-aperture ultra-wide lenses? How about 24-70mm zooms? And what kind of photography do you use these lenses for? We'd love to hear from you.