OM System M.Zuiko Digital ED 40-150mm f/4.0-5.6 R

This OM System zoom spans 40–150mm on Micro Four Thirds cameras. The short end gives a comfortable portrait view; the long end reaches distant action. It suits head-and-shoulders portraits, outdoor sport and nearby wildlife.

You can carry it all day without noticing it. One lens covers portraits, distant detail and everything between. That makes it a simple companion for travel, walks and family days out.

The lens fits the Micro Four Thirds mount, so it pairs with the system's small bodies. Its main trade-off is light gathering. The maximum aperture slows as you zoom in, which favours daylight work over dim interiors.

The lens weighs 6.7 oz (190 g) and measures 2.5 in (63.5 mm) across. The light weight suits long handheld sessions outdoors. A screw-in filter must match the 58mm thread. Our physical score is 64.

The 40–150mm range gives real working room. At 40mm you can frame a portrait from a comfortable distance. Around the middle of the range, headshots need no crowding. At 150mm you make a distant subject much larger, which helps with sport on a far field or a bird at a feeder. One twist of the rotary zoom ring moves you between those views.

Micro Four Thirds is a small format, so the 150mm end frames distant subjects much as a far longer lens would on a bigger sensor. That apparent reach is a strong reason to carry this zoom. A small, light lens covers subjects that usually need something larger.

Light gathering is the constraint. The maximum aperture opens to f/4 at 40mm and slows to f/5.6 at 150mm. In daylight that is workable. Indoors or at dusk you will need a higher ISO or a steadier hold. A distant subject at the long end still stands apart from a busy background, though a faster lens would separate it more. We score these optics 53.

Closest focus is 3 ft (90 cm). That lets you tighten framing on a seated subject or a still arrangement without crowding it. Maximum magnification is 0.16x, which suits a single flower head or a similar small detail.

No stabilisation is built into the lens. Camera shake shows more readily at the 150mm end. For handheld shots, use a faster shutter speed or brace yourself. A monopod or railing gives a steadier platform when light falls. In bright conditions, handholding stays comfortable.

Weather sealing is absent, so keep the lens dry in rain and dust. If conditions turn wet, tuck it away or shoot from cover. The front glass also lacks a fluorine coating, so wipe smudges off with care.

One aspherical element helps correct distortion, where straight edges such as a fence or doorway could otherwise bow. One low-dispersion element helps reduce colour fringing along high-contrast edges, such as dark branches against a bright sky at the long end.

Focusing is internal, so the barrel does not extend as you focus. Our construction score is 54.