This is a fisheye zoom lens from Kenko Tokina. It has a diagonal angle of view of 180 degrees at the wide end, making it suitable for wide-angle underwater photography. I have used it for diving. It is listed with a focus gear. - Brand: Tokina - Model Name: Fisheye 10-17mm F3.5-4.5 DX - Focal Length: 10-17mm - Minimum Focusing Distance: 0.14m - Maximum Aperture: F3.5-F4.5 This lens is for NIKON APS-C cameras, but it can be used on full-frame cameras without vignetting at 15-17mm. Returns are not accepted to prevent product substitution. Focal Length (Wide): ~10mm Focal Length (Telephoto): ~18mm Other Features: Front lens cap included, Rear lens cap included