Pentax DA 55-300mm lens

The HD Pentax DA 55-300mm lens, is a telezoom lens line for the Pentax K-mount. There are 4 generations so far.

HD Pentax DA 55-300mm F4.0-5.8 ED WR

Maker	Pentax
Lens mount(s)	Pentax K mount
Technical data
Type	Zoom
Focus drive	Screwdrive
Focal length	55-300mm
Focal length (35mm equiv.)	82.5-450mm
Crop factor	1.5
Aperture (max/min)	f/4-5.8 / f/22-32
Close focus distance	55.2 in (1.4 m)
Max. magnification	0.28x
Diaphragm blades	6
Construction	12 elements in 8 groups
Features
Manual focus override	Yes
Weather-sealing	Yes
Unique features	Quick-shift focus, filter window, ED glass element, SP (Super Protect) coating, HD coating
Physical
Weight	15.5 oz (440g)
Filter diameter	58mm
Accessories
Lens hood	PH-RBG 58mm
Case	S80-160
Angle of view
Diagonal	29.0-5.4 degrees

The first generation was the SMC Pentax-DA 55-300mm F4-5.8 ED, green side band. It was produced from 2008 to 2013.

The second generation was the SMC Pentax-DA L 55-300mm F4-5.8 ED, silver side band "plastic fantastic". It began in 2010 and is still in production.

The third generation of this lens line up is the HD Pentax DA 55-300mm F4.0-5.8 ED WR, red side band, released in 2013. It added weather sealing.

The fourth generation HD Pentax-DA 55-300mm f/4.5-6.3 ED PLM WR RE, no side band, green front band, was released in 2016. It added Pulse Moter (PLM) for quieter, faster and more accurate auto focus. It is also shorter and about 10% lighter than the third generation, although its max apertures are smaller. It requires the KAF4 lens mount, so Pentax DSLRs before 2013 are not able to use this lens. Other compatible models still need a firmware update before they can use this lens. Some models, such as the Pentax K-30, can potentially bypass this limitation by running a "hacked" Pentax K-50 firmware.