Sigma's unique DX telephoto — the 50-150mm f/2.8 APO II with constant fast aperture for APS-C.
The Sigma 50-150mm f/2.8 APO II EX DC HSM is a unique APS-C telephoto zoom maintaining constant f/2.8 across the 75-225mm equivalent range. Released around 2008 as the second generation, it filled the same niche as the Tokina 50-135mm f/2.8 — a compact, constant-aperture telephoto designed specifically for APS-C rather than adapted from full-frame glass.
Optical performance is good. Sharpness is very good from f/2.8, particularly in the 50-100mm range. The APO designation with SLD elements provides excellent chromatic aberration control. The constant f/2.8 aperture ensures consistent exposure and depth of field throughout the zoom. HSM motor provides fast, quiet autofocus. Bokeh is smooth at wider apertures.
Nikon F mount, APS-C only. Filter thread is 67mm. Weight is approximately 780 grams — moderate for a constant f/2.8 telephoto. Build quality is solid with the EX professional designation. No image stabilisation — the main limitation. The APO II designation indicates improved optics over the original version.
Available on the used market at reasonable prices. Check AF accuracy and smooth zoom operation. A unique lens with few direct competitors — the constant f/2.8 in a compact DX telephoto was innovative. The lack of stabilisation is the main practical drawback. Best for sports and events in good light on APS-C bodies.