Sigma's earlier super-tele with OS — same as ID 1084, 150-500mm f/5-6.3 before 150-600mm.
The Sigma 150-500mm f/5-6.3 DG OS HSM is Sigma's earlier super-telephoto zoom with OS optical stabilisation providing approximately 4 stops — predating the improved 150-600mm Contemporary and Sports replacements that offered more reach.
Optically acceptable with APO glass and SLD elements controlling chromatic aberration. Sharp in the centre at mid-focal lengths but soft at 500mm wide open. OS stabilisation is essential at these extreme focal lengths. HSM motor provides fast quiet autofocus.
Available for Canon EF, Nikon F, and Sony A mounts with 86mm filter thread — enormous. Approximately 1780g — very heavy requiring tripod or monopod support. No weather sealing. Tripod collar included as mandatory at this weight.
Available used very cheaply making it one of the most affordable ways to get 500mm reach with stabilisation. The 150-600mm Contemporary and Sports are dramatically better — sharper and with more reach. Only for absolute budget super-telephoto needs with tripod support.