The Sigma 50-120mm F2.8 DC OS | Contemporary is a compact telephoto zoom for APS-C mirrorless cameras, with a constant F2.8 aperture and coverage equivalent to approximately 75mm to 180mm in 35mm terms. Its combination of telephoto reach, a large aperture and portability suits subjects ranging from portraits to outdoor events.
The FUJIFILM X-mount version measures ⌀66.8mm x 99.3mm / ⌀2.6in. x 3.9in. and weighs 390g / 13.8oz., keeping the lens easy to carry without giving up its constant F2.8 aperture. Lens length is measured from the front of the lens to its mount.
Its 18-element, 13-group optical design includes one FLD element, three SLD elements and four aspherical elements. This arrangement balances compact dimensions with correction of optical aberrations, helping maintain high contrast from the center to the edges throughout the zoom range. At the telephoto end, pronounced background blur and compression can isolate portrait subjects or keep perspective restrained in product photography.
Alongside Sigma's 10-18mm F2.8 DC DN | Contemporary and 18-50mm F2.8 DC DN | Contemporary, this lens completes a constant-F2.8 zoom lineup spanning ultra-wide-angle through telephoto. Sigma lists the combined weight of the three lenses at about 2 pounds (935g), making the series an option for building a portable, large-aperture system.
- - Fast, quiet autofocus: Sigma's HLA (High-response Linear Actuator) linear motor moves the focusing optics directly, without gears or other intervening mechanical parts, for high-speed, high-precision focusing.
- - Optical stabilization: The OS2 algorithm provides 6.5 stops of stabilization at the wide end and 4.5 stops at the telephoto end. These ratings follow CIPA guidelines and were measured at 50mm and 120mm using an APS-C mirrorless camera.
- - Reduced focus breathing: The optical design limits changes in angle of view during focusing, helping video compositions remain steady as focus shifts.
- - Simplified controls: The lens omits focus-mode and OS switches for a minimal interface designed to remain straightforward to operate.
For outdoor use, the lens has a dust- and splash-resistant structure with sealing at the mount connection, manual focus ring, zoom ring and cover connection. A water- and oil-repellent coating on the front surface makes water easier to wipe away and helps prevent oil and grease from adhering. The lens is not waterproof: avoid large splashes, as water entering the lens can cause a serious malfunction.
Every lens undergoes testing with Sigma's proprietary MTF measurement system. Sigma also lists mount conversion service as available for this lens.
