smc PENTAX DA 55-300mm f/4-5.8 ED. The versatile DA 55-300mm ED zoom lens offers an extreme telephoto zoom range, perfect for those moderate to long shots. ED elements compensate for chromatic aberration, while the PENTAX SP coating protects the exposed lens elements. Developed specifically for PENTAX digital SLRs, the DA 55-300mm ED zoom has a focal length equivalent to 82.5mm to 450mm in the 35mm format.