The atx-i 11-16mm F2.8 CF wide-angle zoom opens up a whole new world of imaging possibilities. Designed for use with APS-C DSLRs, with an effective focal length range of approximately 16-24mm, the atx-i 11-16mm F2.8 CF offers a constant aperture of f/2.8 throughout the range, an f/22 minimum aperture, and close focusing capability of 0.3 meters (about 1 ft), thus hitting all the marks for photographers who want to take advantage of all the exciting visual potential the lens affords.