Sigma APO 300-800mm f/5.6 EX DG HSM - Canon EF, Nikon F, Sigma SA Mount

Known colloquially as 'Sigmonster', this ultra-telephoto zoom provides a constant f/5.6 aperture throughout its expansive focal range. The optical design incorporates two ELD glass elements to combat chromatic aberrations across the zoom range. It is a substantial lens, weighing nearly 6kg, and is best suited for stationary wildlife or field sports photography where a tripod or heavy-duty gimbal is available. Second-hand units should be checked for smooth zoom and focus ring operation, as the internal mechanisms handle significant weight. Ensure the HSM motor focuses accurately without hunting. SDS checks for fungal growth on the large internal elements and verifies that the heavy-duty tripod foot is stable. Given its size, the external barrel often shows signs of paint wear, particularly on the hood and mounting points.