SIGMA APO 400mm F5.6 APO telephoto lens. - Brand: SIGMA - Accessories: Lens cap - Color: White - Focal Length: 400mm - Maximum Aperture: F5.6 Thank you for viewing. I selected a mount for listing convenience, but the correct mount is Yashica Contax (C/Y) mount. The focus ring and aperture blades function without any problems. The included hood also works, and it has a red line indicating it is an APO lens. Please check the condition of the aperture blades in the photos. There is some haze on the middle element, so it is being sold as junk.