Sigma announces two more I Series primes, a faster 24mm f/2 and a 90mm f/2.8 (Hands-on & Gallery)
posted Thursday, September 9, 2021 at 8:30 AM EDT
Back at the end of 2020, Sigma launched a new family of prime lenses, the "I Series," which encompassed the compact 45mm f/2.8 lens that debuted alongside the Sigma fp mirrorless camera as well as three additional lightweight primes lenses -- a 24mm f/3.5, a 35mm f/2 and a 65mm f/2. So far, all of these lenses share Sigma's "Contemporary" product line naming designation and all feature compact, stylish designs, premium construction and manual aperture rings.
Today, Sigma is adding two more members to the I Series family, an additional 24mm lens with a faster aperture and a longer, telephoto 90mm f/2.8 prime. The new 24mm f/2 DG DN Contemporary lens is, however, not replacing the existing 24mm f/3.5 lens. It's an additional option for those who want better low-light performance with the same classic wide-angle field of view. The faster 24mm f/2 lens is, therefore, the preferred lens for subjects such as astrophotography, interior shooting and other low-light applications. The f/3.5 version, meanwhile, serves as a smaller, lighter and more affordable 24mm prime lens.
Meanwhile, the new 90mm f/2.8 DG DN Contemporary lens is the longest lens in the I Series lineup so far. The 90mm mid-telephoto focal length plus a bright f/2.8 aperture make it an ideal option for portraiture as well as general photography purposes where you want some reach and compression as well as nice subject isolation. Plus, the lens has a maximum magnification ratio of 1:5, which makes it nice for close-up photography.
I had an opportunity to get an early hands-on look at both of these new Sigma primes, and in addition to some handling notes, I also have an initial batch of real-world sample images from both lenses -- shot using the high-resolution Panasonic S1R.
Design & Construction
By design, the Sigma I Series lenses all share several common features with regard to both design and construction, including all-metal construction on the exterior as well as high-precision metal internal components, dust- and splash-proof gaskets around the lens mount, and knurled metal aperture and focusing rings. The 24mm f/2 DG DN C is obviously no exception to this, nor is the new 90mm lens.
In the hand, the build quality feels outstanding, much like I've experienced with other modern Sigma lenses. The lens is incredibly solid and well built, with a nice heft to it. The aluminum construction is indeed a nice, premium touch. Many of Sigma's other modern lenses utilize a plastic-like "Thermally-Stable Composite" material for much of the lens barrel, and while those lenses feel just as solid and nicely built, there is something pleasing about a metal lens barrel.
Despite the use of metal over plastics, the lens is still surprisingly lightweight -- and compact -- for a full-frame-format f/2 wide-angle lens. The new 24mm f/2 is, as expected, a bit larger and heavier than its dimmer f/3.5 sibling, but the lens is still extremely portable and compact. The 24mm f/2 weighs in at 365g (12.9oz.) and measures 70mm in diameter and a length of 72mm (2.8in x 2.75in). By comparison, the 24mm f/3.5 lens weighs just 225g (7.9oz) and measures 64 x 50.8mm (2.5in x 2in).
The other distinguishing feature of this lens is the addition of a manual aperture ring, a feature that Sigma doesn't often include on its other lenses. The aperture ring has marked full- and third-stop increments from f/2 to f/22 (as well as an "A" mode past f/22 for camera dial-controlled aperture changes). The metal ring has a nice, deeply ridged (or knurled) texture for an easy grip. In use, the aperture ring, like other aspects of this lens's build quality, feels top-notch. There's a pleasing amount of resistance and solid-feeling detents to the "clicked" ring when you rotate it, such that there's little risk of accidentally moving the ring. Unlike the Sigma 35mm f/1.2 DG DN Art, for instance, the aperture ring on this lens -- and the other I Series lenses -- don't include a de-click toggle switch; something to keep in mind for video shooters.
The focusing ring, meanwhile, rotates with a very pleasant smooth feel. The lens doesn't offer any sort of focusing distance scale, nor is there any change in focus ring behavior when switching into Manual Focus mode. Without any hard or soft stops, the focusing ring will continue to rotate indefinitely.
Other physical features of the Sigma 24mm f/2 DG DN include a dedicated AF/MF toggle switch on the side, a 9-bladed rounded aperture diaphragm, a 62mm filter thread size and a petal-shaped metal lens hood.
Optics & Autofocus
In terms of the optical layout, this brighter lens features an altogether different optical design than the f/3.5 version. This new lens uses a total of 13 elements (three more than the f/3.5 version) placed into 11 groups. The lens also includes one FLD ("F" Low Dispersion -- glass element similar to fluorite glass) element, two SLD (Special Low Dispersion) elements and two aspherical elements. The SLD and FLD elements help suppress axial chromatic aberrations, while the pair of aspherical elements help correct for spherical and comatic aberrations, the latter of which being particularly important for night sky photography. According to Sigma, the use of the two high-precision glass-molded aspherical elements helped them reduce the overall number of lens elements needed and thus allowed for reduced size and weight.
Like the other I Series lenses, the Sigma 24mm f/2 DG DN lens uses a high-speed stepping motor autofocus system that provides both fast and essentially silent AF performance. Offered in both L-mount and Sony E-mount versions, the lens is compatible with Sony's DMF and AF+MF modes.
Interestingly, the minimum focusing distance is quite different than that of the f/3.5 version. This new 24mm prime focuses down to just 24.5cm (9.65in) -- offering a maximum magnification ratio of 1:6.7 -- whereas the f/3.5 lens could focus much closer, down to 10.8cm (4.3in) for a 1:2 maximum magnification ratio.
Design & Construction
As expected, the overall design, construction and operability of the 90mm f/2.8 I Series lens is essentially the same as with the 24mm f/2 and its other Contemporary siblings. The lens features the same overall design, with a manual aperture ring and metal construction. The lens feels just as impressive in terms of fit and finish as the 24mm f/2 DG DN lens. The specific physical dimensions are, however, slightly different with the 90mm f/2.8 lens being an overall smaller lens, in both length and diameter. Without the lens hood attached, the 90mm f/2.8 lens is only 59.7mm (2.35in.) in length.
Adding the comparatively large barrel-shaped lens hood adds approximately 4cm (1.6in) of length onto the lens, making it all ever-so-slightly longer than the 24mm f/2 with its hood attached. The 90mm lens is also smaller in diameter, at just 64mm (2.5in), and uses a 55mm filter thread. The 55mm filter size is the same as on the earlier 24mm f/3.5 and 45mm f/2.8 lenses, so there is some easy cross-compatibility with filters. (The 24mm f/2 lens shares the same 62mm filter size as the 65mm f/2 DG DN lens.)
Optics & Autofocus
The Sigma 90mm f/2.8 DG DN lens uses a total of 11 lens elements situated into 10 groups and includes a total of five SLD (Special Low Dispersion) elements and a single aspherical element. As in the wider lens, the use of the SLD glass elements help combat axial chromatic aberration, while the aspherical elements help produce high-resolution images across the frame as well as pleasing bokeh performance. The lens also features a 9-bladed aperture diaphragm, which further helps create smooth out-of-focus areas and visually-pleasing bokeh.
In terms of autofocus, the 90mm lens uses a similar high-speed stepper motor AF system for fast and quiet AF performance, and also supports Sony's DMF and AF+MF focusing modes. The lens has a minimum focusing distance of 50cm (1.6ft) and a 1:5 maximum magnification ratio. It's not a macro lens by any means, but the lens focuses a bit closer than the 65mm f/2 lens; with the longer focal length of the 90mm lens, you can capture decent close-up images.
Pricing & Availability
Both of the new Sigma I Series prime lenses are scheduled to go on sale in late September and both at the same estimated retail price of US$639.99.