The Sigma 50-120mm F2.8 DC OS | Contemporary combines a constant F2.8 aperture with a compact telephoto zoom design for APS-C mirrorless cameras. The Canon RF version measures ⌀69.0mm x 97.0mm and weighs 410g / 14.5oz., bringing the lens's large-aperture shooting capabilities into a portable package.
Its 18-element, 13-group optical design includes one FLD element, three SLD elements and four aspherical elements. This combination balances compact dimensions with correction of optical aberrations throughout the zoom range. The design maintains high contrast from the center of the image to the edges rather than concentrating performance only in the middle of the frame.
Telephoto rendering provides pronounced background blur and a compressed perspective for a range of subjects. Portraits can emphasize the subject against the background, while product photographs can use the flatter perspective to keep apparent depth in check. Sigma also positions the lens for outdoor events, where its telephoto reach and portable design suit varied scenes.
The 50-120mm joins Sigma's 10-18mm F2.8 DC DN | Contemporary and 18-50mm F2.8 DC DN | Contemporary in a three-lens zoom series. Together, these lenses cover ultra-wide-angle through telephoto shooting while maintaining a constant F2.8 aperture, offering a way to build a versatile APS-C system around compact, large-aperture zooms.
For video, the optical design reduces focus breathing—the change in angle of view that can occur as focus moves. Suppressing these shifts helps the composition remain more consistent during focusing, supporting more natural-looking focus transitions without a pronounced change in framing.
Sigma's HLA (High-response Linear Actuator) powers high-speed autofocus. This proprietary linear motor moves the focusing lens directly, without gears or other intervening mechanical parts. The direct-drive arrangement delivers quiet, high-precision focusing alongside the fast autofocus response.
Optical stabilization uses Sigma's OS2 algorithm, with compensation rated at 6.5 stops at the wide end and 4.5 stops at the telephoto end. These ratings are based on CIPA guidelines, measured at focal lengths of 50mm and 120mm using an APS-C mirrorless camera.
The exterior takes a minimalist approach to controls. Dedicated focus-mode and OS switches have been omitted, keeping the lens's physical interface simple despite its autofocus and stabilization features.
Dust- and splash-resistant construction uses sealing at the mount connection, manual focus ring, zoom ring and cover connection. The front surface also has a water- and oil-repellent coating that makes water easier to wipe away and helps prevent oily residue from adhering. The lens is not waterproof: avoid large amounts of splashing water, as water entering the lens can cause a major malfunction.
- • An 11-blade rounded diaphragm controls the aperture.
• Minimum focusing distance ranges from 23cm / 9.1in. at the wide end to 55cm / 21.7in. at the telephoto end.
• Maximum magnification is 1:3 at the wide end and 1:4.7 at the telephoto end.
• The lens accepts 55mm filters.
Every lens is checked using Sigma's proprietary MTF measuring system. Sigma also lists its Mount Conversion Service as available for this lens.
