HD PENTAX-DA18-50mm F4-5.6 DC WR RE

This standard zoom lens has been developed as a compact, easy-to-use everyday lens that meets user demand for a downsized, high-resolution digital SLR imaging system. Thanks to its retractable mechanism — employed for the first time in the PENTAX K-mount lens system — it provides the world’s shortest length in the stored position: just 41 millimeters*.

...

Despite its ultra-compact design that assures outstanding portability, it also features the PENTAX-original HD Coating, super-low dispersion glass elements and aspherical elements to effectively compensate various aberrations for sharp, high-contrast, well-balanced images. Its built-in DC motor assures smooth, quiet autofocus operation, while its weather-resistant body makes it extremely dependable and durable in demanding outdoor conditions.

* The world’s shortest standard zoom lens for use with digital SLR cameras (as of February 1, 2015, based on RICOH IMAGING research)