This lens replaces the AF235 II (20-35mm f/3.5-4.5) in Tokina's quality middle line of AF series lenses. The AF193 is constructed with high refraction

This lens replaces the AF235 II (20-35mm f/3.5-4.5) in Tokina's quality middle line of AF series lenses. The AF193 is constructed with high refraction, low dispersion (HLD) glass and multicoated lens elements produced by Hoya Corporation, the world's largest manufacturer of optical glass. While using the same mechanical design as the AF235 II, the AF193 has barrels made from black poly carbonate to reduce the overall weight of the lens, making it more convenient for photographers to carry while traveling, hiking or engaged in other activities where encumbrance is an issue.