Pentax smc DA 18-55mm f/3.5-5.6AL WR

The smc DA 18-55mm f/3.5-5.6AL WR is a standard zoom for Pentax K mount APS-C cameras. At 18mm it suits landscapes, interiors and group shots. At 55mm it works for portraits and tighter framing. One lens covers most subjects on a day out.

The trade-off is light gathering. The maximum aperture runs from f/3.5 at 18mm to f/5.6 at 55mm, so the lens is weakest in dim rooms and evening light. Released in 2009, this is an older design, so check that its features still meet your needs before buying.

The sealed, light build makes it an easy lens to keep on the camera for travel, walks and family pictures.

At 8.1 oz (230 g), this zoom is light enough for all-day handheld shooting. The body measures about 2.72 in (69 mm) across and 2.68 in (68 mm) long, so it stays compact on the camera. A 52mm filter threads directly onto the front. The physical score is 57/100.

On the APS-C sensor, 18mm gives a usefully wide view for streets, interiors and landscapes. Zoom to 55mm and the same lens frames portraits and detail shots without stepping back. That span makes it a practical single lens for varied daily work.

The aperture is the main constraint. It opens to f/3.5 at the wide end and drops to f/5.6 at 55mm. Indoors or at dusk, expect slower shutter speeds or a higher ISO to keep shots sharp. Outdoors in daylight, the smaller opening matters far less.

At 55mm wide open you can still separate a portrait subject from its background. The modest aperture limits how strongly the background blurs. Stopped down, depth of field deepens for landscapes and groups.

Close focusing reaches 0.8 ft (25 cm) from the subject, useful for detail shots on a walk. Maximum magnification is 0.34x, so flowers, food and small objects fill a good part of the frame. The optics score is 54/100.

The WR in the name stands for weather resistant. Sealing keeps dust and moisture out of the lens, so you can keep shooting in drizzle or on a dusty trail. A fluorine coating on the front element helps water and oil slide off, making the glass easier to wipe clean.

There is no built-in image stabilization. Handheld work in dim light depends on a steady hold, support, or a shutter speed fast enough for the scene. The features score is 52/100.

A zoom lock is absent too. Without one, the barrel can creep when the lens hangs pointing down, so check the framing before you raise the camera.

The optical formula uses 11 elements in 8 groups, including one aspherical element and one low-dispersion element. The aspherical surface helps correct distortion, which can bow the straight edges of buildings and horizons at 18mm. The low-dispersion glass helps reduce chromatic aberration, the coloured fringes that can appear along high-contrast edges in backlit scenes. The construction score is 31/100.