OM SYSTEM 12-40mm f/2.8 PRO II Review: A Reliable Everyday Zoom

The OM SYSTEM M.Zuiko Digital ED 12-40mm f/2.8 PRO II is one of those lenses you can carry almost anywhere without worrying about what you might miss. It covers the 24-80mm equivalent range, which means you can handle landscapes, portraits, events, and travel with just this one piece of glass. Having a constant f/2.8 aperture across the zoom range makes it even more valuable, since you don’t need to compromise in low light or sacrifice depth of field control.

Coming to you from Waterfall Joe, this detailed video takes a close look at the OM SYSTEM M.Zuiko Digital ED 12-40mm f/2.8 PRO II lens. It isn’t a brand-new optical design: the glass elements and rendering remain consistent with the original Olympus version from 2013. However, the refresh brings real improvements. The most practical update is its IP53 weather-sealing, a noticeable upgrade from the original’s minimal splash protection. That means hiking through rain or shooting around waterfalls is less of a risk. Joe points out that the build quality is excellent, with metal construction that feels solid in hand, and the focus clutch gives you fast control when you want to switch to manual. It weighs just 382 g, so you can take it on long walks without your bag feeling overloaded.

Joe highlights how well it balances on larger bodies like the OM-1, while still being manageable on smaller ones like the OM-5. The constant f/2.8 aperture means you don’t lose performance when you zoom, giving you confidence in both daylight and darker environments. He also stresses how sharp it is, even wide open, which is something that sets it apart from cheaper alternatives in the Micro Four Thirds system.

Key Specs

• Focal Length: 12 to 40mm (35mm Equivalent: 24 to 80mm)

• Aperture: Maximum f/2.8, Minimum f/22

• Lens Mount: Micro Four Thirds

• Coverage: Micro Four Thirds

• Minimum Focus Distance: 7.9" / 20 cm

• Magnification: 1:3.33 (0.3x)

• Optical Design: 14 Elements in 9 Groups

• Aperture Blades: 7, Rounded

• Focus Type: Autofocus

• Image Stabilization: No

• Filter Size: 62 mm

• Dimensions: 2.8 x 3.3" / 70 x 84 mm

• Weight: 13.5 oz / 382 g

Joe also compares it to alternatives. Within OM SYSTEM’s own lineup, the smaller and lighter 12-45mm f/4 is a strong option if you want to save weight and don’t need f/2.8, while the 12-100mm f/4 PRO offers an incredible all-in-one solution with built-in stabilization. He makes the case that the 12-40mm sits in a sweet spot: compact enough for travel, fast enough for low light, and versatile enough to serve as your main lens. For Panasonic users, the Leica 12-60mm f/2.8-4 provides more reach but at the cost of low-light performance.

The video isn’t just about specs; it also shows the lens in real-world use. Joe takes it hiking through Quinnipiac River State Park, capturing both wide forest scenes and close details of trees and vines. He demonstrates how practical it is when paired with a circular polarizer, pointing out how it changes the look of foliage and water. It underscores the lens’ versatility for both everyday outings and travel adventures. Check out the video above for the full rundown from Joe.