Pentax's constant f/2.8 standard zoom — same family as ID 884, SDM motor version.
The Pentax DA 16-50mm f/2.8 ED AL SDM is a fast constant-aperture standard zoom for Pentax APS-C K-mount cameras. DA = APS-C coverage; SDM = Supersonic Drive Motor (ultrasonic AF); f/2.8 constant throughout. Pentax K mount.
f/2.8 constant aperture. 16-50mm zoom range (approximately 24-76mm equivalent on APS-C 1.5× crop). SDM Supersonic Drive Motor AF (quiet). ED + AL elements. At approximately 565g. 77mm filter thread. Pentax K mount (APS-C).
The SDM motor provides quiet and fast autofocus suitable for event and video shooting. The constant f/2.8 aperture through the 16-50mm range is well-suited for available-light indoor photography and events. DA designation confirms APS-C coverage only — vignettes on hypothetical full-frame Pentax bodies.
On the used market the Pentax DA 16-50mm f/2.8 SDM is a professional APS-C standard zoom. Condition checks: 77mm front element, SDM AF motor response, zoom ring smoothness, ED element quality. Pentax K mount — APS-C coverage (DA designation).