The Pentacon auto 29 mm f/ 2.8 is a wide-angle prime lens for 35-мм SLR cameras with the M42 Screw mount.
It came in auto and electric modifications. The latter had multi-coating (Picture 4)
It is sharp on stopping down and has some soft effect when wide open. It is not well resistant to back light and has a pronounced distortion. Background blurring is not notable. It is good for macrography and perspective enhancement.