Sigma's earlier 'Bigma' — 50-500mm without OS, the original extreme-range superzoom for DSLRs.
The Sigma 50-500mm f/4-6.3 EX APO DG HSM is the earlier, non-stabilised version of Sigma's extreme 10x super-telephoto zoom. Covering 50-500mm on full-frame, it was nicknamed 'Bigma' for its enormous size — the original extreme-range zoom.
Optically adequate — sharp in the centre at mid-focal lengths but soft at 500mm. APO glass with SLD elements helps control chromatic aberration. HSM motor provides fast, quiet AF. No image stabilisation — a significant limitation at 500mm. Full-frame coverage.
Nikon F mount with 86mm filter thread. Approximately 1900g — very heavy. Tripod collar included. No weather sealing. Full-frame coverage. Minimum focus distance 50cm at 50mm, 180cm at 500mm.
Available used very cheaply. The OS version added stabilisation and is much more practical. 500mm without stabilisation is extremely challenging handheld. The 'Bigma' name is affectionate but the size is genuinely impractical. Only useful on a stable support.