Sigma's stabilised 1:1 macro with OS — rare in macro lenses — at a lower price than the Canon L equivalent.
The Sigma 105mm f/2.8 EX DG Macro OS HSM is Sigma's professional 1:1 macro prime for full-frame DSLR bodies, providing the 105mm working distance that creates useful clearance between lens and subject at maximum magnification. OS (Optical Stabiliser) is built in — enabling handheld macro photography that unstabilised 105mm macros require a tripod to achieve. The EX DG designation indicates Sigma's professional-grade optical quality for full-frame sensors.
The optical design uses 16 elements in 11 groups. Nine rounded aperture blades produce smooth bokeh. The 62mm filter thread is standard for macro primes in this focal length range. At 725g the lens is substantial for a macro prime. Minimum focus distance of 0.31m achieves 1:1 magnification. OS provides handheld stability for macro and close-up work. HSM motor provides fast, quiet AF with full-time manual override. Constant f/2.8 maximum aperture.
The OS mechanism is the Sigma 105mm macro's key practical advantage over the Nikon AF-S Micro Nikkor 105mm f/2.8G VR at similar price points on the used market: OS enables handheld macro shots that would otherwise require tripod support, and smooth focus pulls for macro video. At 0.31m MFD the physical working distance between front element and subject provides adequate room for natural lighting setup and ring flash attachment.
On the used market the Sigma 105mm f/2.8 EX DG OS HSM is available at affordable macro prime pricing. Condition checks: OS engagement, HSM AF response at macro distances, and front element condition. Confirm the mount version — available in Canon EF, Nikon F, and Sony A mounts. Compatible with full-frame and APS-C bodies in the specified mount; on APS-C the 105mm provides approximately 160mm equivalent working distance, increasing clearance from the subject.