SMC Pentax-DA 18-135mm f/3.5-5.6 ED AL IF DC WR Zoom Lens Pentax Lenses K mount 21977. A compact and lightweight weather resistant lens the SMC Pentax-DA 18-135mm f/3.5-5.6 ED AL [IF] DC WR features a versatile zoom range ideal for many subjects from landscapes to portraits or sports.. Pentax. 21977. 027075173767