Sigma's budget full-frame telephoto with OS — 70-300mm at variable aperture with stabilisation.
The Sigma 70-300mm f/4-5.6 DG OS is a budget full-frame telephoto zoom with OS (Optical Stabiliser) — adding stabilisation to the basic 70-300mm class. It provides an affordable way to get stabilised telephoto reach on full-frame DSLRs.
Optically basic — acceptable centre sharpness at mid-focal lengths but soft at 300mm. OS provides approximately 4 stops of stabilisation — the key feature. AF is adequate. The DG designation means full-frame optimised. Variable aperture f/4-5.6.
Available for multiple mounts. 62mm filter thread. Approximately 610g. No weather sealing. Full-frame coverage. Minimum focus distance 150cm. The OS version is a meaningful upgrade over the non-stabilised APO DG Macro.
Available used very cheaply. The OS makes this more practical than the non-stabilised version. Still basic optics compared to first-party IS/VR options. For absolute budget stabilised telephoto needs. Check for smooth OS operation.