This auto focus circular fisheye lens has an angle of view of 180 degrees in all directions. It is exclusively designed for digital SLR cameras with the APS-C size image sensor. When used in conjunction with digital SLRs with APS-C size image sensors, it produces circular image within the frame. The fast f/2.8 maximum aperture produces a bright image in the viewfinder making this lens ideal for low light photography. This circular fisheye lens has a minimum focusing distance of 13.5cm & a maximum magnification of 1:6 making it particularly useful for close-up photography. SLD (Special Low Dispersion) glass provides effective compensation of chromatic aberration & Sigma’s Super Multi-Layer coating minimises flare & ghosting. It is equipped with an inner focusing system that creates high definition & excellent image quality over the whole frame. The HSM (Hyper Sonic Motor)ensures fast & quiet autofocusing & allows full-time manual focus override by rotation of the focus ring. This lens is ideal for photographers using computer stitching software which requires circular fisheye images to be input, resulting in stitched panoramas. Due to the quantifiable angle/area relationship it produces, this lens can be used for scientific applications such as solid angle measurements of cloud distribution over the sky, or vegetation distribution of the rain forest canopy. A holder at the rear of the lens accepts gelatin filters. 4.5mm f/2.8 EX DC HSM Circular Fisheye Fitted Padded Case Front & Rear Caps Filter Template Instruction Manual 1 Year Warranty Card 2 Year Extended UK Warranty Card