OM System ED 12-40mm f/2.8 PRO II

OM System released the ED 12-40mm f/2.8 PRO II in 2022, and it remains in production. It is a standard zoom for Micro Four Thirds cameras, covering wide scenes at 12mm and tighter portraits at 40mm. That span suits travel, street and everyday assignments where one lens must do varied work.

The maximum aperture is a constant f/2.8.

The main trade-off is control. Focusing is manual only, and the lens offers no stabilization or weather sealing. It suits a photographer who works slowly and deliberately, not one chasing fast action.

At 13.5 oz (382 g), the lens stays light for a long day of shooting. Its 2.75 in (69.9 mm) width and 3.31 in (84 mm) length keep it compact on the camera. The front takes no screw-in filter. It scores 93/100 for physical design in our ratings.

The 12–40mm range runs from wide angle to short telephoto. At 12mm you can frame architecture, interiors and sweeping landscapes. The 40mm end suits portraits, street scenes and tighter detail, so one zoom handles a full day of varied subjects. Between them, the middle lengths handle walkabout framing without lens changes.

The maximum aperture stays at f/2.8 through the whole zoom. That keeps exposure even as you change framing, and it holds shutter speed up in dim rooms or evening streets. At 40mm, f/2.8 also blurs the background behind a portrait. At 12mm depth of field runs deep, so the wide end mainly buys light.

The lens focuses as close as 0.7 ft (20 cm). Maximum magnification reaches 0.3x, so flowers, food and small products can fill a useful part of the frame. That close, the lens front sits near the subject, and your shadow can fall across it.

Focusing is manual only, so this lens rewards slow, careful work. Close subjects and tripod-composed landscapes give you time to focus precisely. In our ratings it scores 57/100 for optics.

Image stabilization is not built in. For handheld work, use a faster shutter speed or a camera body that stabilises. That matters most in dim rooms and evening streets, where light runs short. Careful handholding, or a tripod, covers the rest.

The lens also lacks weather sealing, so keep it out of rain and heavy dust. No fluorine coating protects the front glass either, so cleaning takes ordinary care.

The zoom is driven electrically through a push-pull control rather than a twist ring. There is no zoom lock, so nothing holds a chosen position for you.

The optical formula uses 14 elements in 9 groups. Four aspherical elements carry specially shaped surfaces that help correct distortion and spherical aberration. That help matters for the architecture and interiors you frame at 12mm, where distortion can bend straight edges.

Two low-dispersion elements help reduce chromatic aberration. That is the colour fringing you can see along high-contrast edges, such as a rooftop against a bright sky. It scores 31/100 for construction in our ratings.