Just received a new zoom lens: Pentax HD DA 55-300mm f/4.5-6.3 ED PLM WR RE Lens for use with my Pentax K-50 16MP Digital SLR Camera with 3-Inch LCD.
This lens is a replacement for the Pentax HD Pentax-DA 55-300mm f/4-5.8 ED WR Lens . However, the new lens is smaller and lighter than the old. More importantly, focus is absolutely silent. The old lens used a mechanical rod to drive focusing. It was noticeably loud, especially if it had to seek focus.
In this photo above, PENTAX DA 18-55mm f/3.5-5.6 AL Weather Resistant Lens for Pentax Digital SLR Camera (Discontinued by Manufacturer) is on the left and the old zoom is on the right. In between the two is the new lens. Extended, the new lens is the same length as the old.