For Canon, Nikon and Pentax DSLRs, the Irix 15mm f/2.4 Blackstone is a rectilinear wide-angle lens with manual focus, ideal for landscape work. The aluminum-magnesium alloy housing is sealed to protect from dust and splashes, with an engraved fluorescent focus scale that’s designed to be readable in dim light. Focus is adjusted with a large, grooved ring and can be locked by turning an adjacent ring. A sliding door on the removable lens hood allows access to rotate filters. Estimated street price: $599. Contact: Irix, irixlens.com.