Sigma 50-100mm f/1.8 DC HSM Art Lens for Nikon F CRK additional lens configurations are available:

additional lens configurations are available: three different AF speed modes to modify how quickly the lens changes focus

Group-Area AF: This mode treats smaller groups of AF points as a single point for a wider field of recognition

it has a fast f/2 maximum aperture

This feature allows the camera operator to add filters over the lens without taking up a filter stage in a matte box

Through the L-Mount Alliance

Sigma 50-100mm f/1.8 DC HSM Art Lens for Nikon F CRK additional lens configurations are available:Pairing a versatile range of telephoto focal lengths with a fast constant maximum aperture, this 50 100mm f 1. 8 DC HSM Art Lens from Sigma is designed for DX format Nikon F mount DSLRs, and provides a 75 150mm equivalent focal length range. The bright constant maximum aperture offers consistent low light performance throughout the zoom range and also affords greater control over focus placement for shallow depth of field and selective focus