Combining reach and speed, the Pentax K-mount Sigma APO 300mm f/2.8 EX DG is a super-telephoto prime also characterized by its advanced optical and physical design. Its fast f/2.8 maximum aperture aids in isolating subjects using depth of field and also supports working in low-light conditions. Designated an apochromat, this lens uses a pair of extra-low dispersion elements to effectively eliminate color fringing and chromatic aberrations for high clarity and color accuracy throughout the aperture range. A multi-layer coating has also been applied to lens elements to control flare and ghosting for improved contrast and clarity.
Benefitting the optical attributes is an internal focus system, which provides quick autofocus performance with full-time manual focus override. The physical design also incorporates a fixed, rotating tripod collar for easy attachment to a tripod or monopod, and a drop-in filter slot permits working with rear 46mm filters, such as the included circular polarizer filter.