Sigma announces 28-70mm f/2.8 DG DN Contemporary, the lightest f/2.8 standard zoom for full-frame mirrorless cameras
posted Wednesday, February 24, 2021 at 7:30 AM EST
Sigma has announced a new Contemporary-series full-frame mirrorless zoom lens, the 28-70mm f/2.8 DG DN Contemporary. The 28-70mm f/2.8 DG DN C lens is based on Sigma's existing 24-70mm f/2.8 DG DN Art lens, but starting the new zoom's focal length at 28mm results in a significantly smaller and lighter lens without sacrificing optical performance. Per Sigma, the 28-70mm f/2.8 DG DN C is the smallest and lightest full-frame f/2.8 standard zoom lens for mirrorless cameras. The 28-70mm f/2.8 DG DN C is not meant to replace the 24-70mm f/2.8 Art lens in Sigma's lineup but rather offers photographers a lighter and more compact alternative.
Sigma 28-70mm f/2.8 DG DN Contemporary Key Features
- 28-70mm full-frame lens with constant f/2.8 aperture
- 75.4° to 34.3° field of view
- Weighs only 16.6 oz. (470g)
- Minimum focus distance of 7.5-15" (19-38cm)
- Compatible with high-speed autofocus
- Compatible with lens-based optical correction
- 16 elements in 12 groups
- Includes 2 FLD elements, 2 SLD elements and 3 aspherical elements
- 9-blade rounded diaphragm
- Weather sealing at lens mount
- Available for L-mount and Sony E-mount
The optical design of the Sigma 28-70mm f/2.8 DG DN C lens is based on the 24-70mm f/2.8 DG DN Art lens. Sigma promises that the new 28-70mm lens delivers 'outstanding optical performance throughout its zoom range.' The 28-70mm f/2.8 lens includes 16 elements in a dozen groups, three fewer elements and groups than the 24-70mm f/2.8 Art lens. The 28-70mm has three aspherical lenses, two SLD lenses, and a pair of FLD lenses. The lens incorporates Super Multi-Layer Coating, Nano Porous Coating and coating on the front element to repel water and oil.
By reducing the focal length range from 24-70mm to 28-70mm, Sigma has reduced the weight of the lens from 29.5 oz. (835 grams) to 16.6 oz. (470g), which is a roughly 40% reduction in total weight. When comparing L-mount versions, the 28-70mm lens is 3.99" (101.5mm) in length and has a maximum diameter of 2.84" (72.2mm). The 24-70mm f/2.8 lens, on the other hand, is 4.84" (122.9mm) long and has a maximum diameter of 3.46" (87.8mm). The filter thread size is also quite different, with the 28-70mm lens using a 67mm filter, whereas the 24-70mm f/2.8 Art uses a much larger 82mm filter.
In addition to a different focal length range, the 28-70mm compromises slightly with weather sealing. The new zoom has dust- and splash-proofing at the mount only, whereas the 24-70mm f/2.8 Art lens incorporates sealing throughout the lens barrel. There are also different controls on the two standard zoom lenses. The 28-70mm f/2.8 has only a focus mode switch on the barrel, whereas the 24-70mm f/2.8 Art lens has a focus mode switch, AFL button and a zoom lock switch.
The 28-70mm f/2.8 DG DN Contemporary lens consists primarily of lightweight parts. The lens is built using Thermally Stable Composite (TSC), which Sigma promises offers excellent build quality without compromise. TSC has a similar level of thermal shrinkage as aluminum, so performance should be stable across a wide range of temperatures.
The reduction in optical complexity results in the Sigma 28-70mm f/2.8 DG DN C requiring only a single lightweight focusing element, and the AF stepping motor unit is small as well. Sigma promises quick and quiet autofocus. The 28-70mm has a minimum focusing distance range of 7.8-15" (19-38cm), which results in a 1:3.3 maximum reproduction ratio at 28mm and 1:4.6 at 70mm. This is comparable to the Sigma 24-70mm f/2.8 Art lens, which has a slightly better minimum focusing distance.
The Sigma 28-70mm f/2.8 DG DN Contemporary lens is available in L-mount and Sony E-mount. The lens is compatible with Sigma's USB dock UD-II (for L-mount only). The lens is made in Japan at Sigma's Aizu Factory and will be available starting on March 12 with a suggested retail price of $899 USD.