Pentax HD DA 55-300mm f/4.5-6.3ED PLM WR RE

This Pentax telephoto zoom covers 55–300mm on APS-C cameras with the K mount. That reach suits birds, wildlife and outdoor sport, where subjects keep their distance. Pentax introduced it in 2016, so it is an older design.

The trade-off is speed. The maximum aperture falls from f/4.5 to f/6.3 across the zoom, and there is no built-in stabilization. In return, the lens stays light and weather sealed, which suits long days outdoors.

Anyone shooting from a fixed spot, such as a hide or a touchline, will use the long end most.

It weighs 15.6 oz (442 g) and runs 3.5 in (89 mm) long with a 3.01 in (76.5 mm) body. That weight carries easily on a long walk. Screw-in filters must match the 58mm thread on the front.

The 55–300mm range frames distant subjects without you moving closer. At 55mm it gives a short telephoto view for portraits and detail. At 300mm it makes small or wary subjects large, from perched birds to players on the far side of a pitch. Zooming between the ends tightens framing as a subject approaches.

Light is the main constraint. The maximum aperture narrows from f/4.5 at 55mm to f/6.3 at 300mm. Bright daylight keeps shutter speeds workable; in shade or at dusk you raise ISO instead. The smaller maximum aperture at the long end also deepens the zone of sharpness, which can help keep a moving animal within focus.

Close work is also possible. The lens focuses to 3.1 ft (95 cm). At its maximum magnification of 0.3x, a frog or a flower head appears at about a third of life size in the frame. Tight portraits of pets also work at the near limit. Nine blades keep the aperture close to round, which helps smooth out-of-focus highlights behind a portrait subject.

Weather sealing protects the lens against rain and dust, so you can keep shooting when conditions change. Wildlife and sport often mean waiting outdoors through poor weather, and the sealing fits that work. The WR in the name marks this protection.

A fluorine coating on the front glass helps water and oil slide off, so the front cleans quickly between frames in damp weather. Dust and fingerprints wipe away with a light touch rather than persistent rubbing.

There is no image stabilization, so a fast shutter or support keeps handheld frames steady. Support here means a monopod, tripod or any steady rest for the camera. There is no zoom lock either, so the barrel can slip when the lens hangs downward. Check the zoom ring position before raising the camera after carrying it at your side.

One ED element sits in the 14-element build. Low-dispersion glass helps reduce chromatic aberration, where colours focus differently and leave coloured fringes along high-contrast edges. A bird against a bright sky shows those edges clearly, so the glass serves this lens's likely subjects. Focusing also works internally, moving elements inside the barrel rather than extending the whole front.