OM System M.Zuiko Digital ED 100-400mm F5.0-6.3 IS II

The OM System M.Zuiko Digital ED 100-400mm F5.0-6.3 IS II is a super-telephoto zoom for Micro Four Thirds cameras. OM System announced it in February 2025 together with the OM-3 as the updated version of the Olympus 100-400mm F5.0-6.3 IS. It is aimed at wildlife, bird and sports photographers who want long reach in a handheld lens. On the 2x crop of Micro Four Thirds, the focal range corresponds to 200-800mm in full-frame terms.

Optical design

The lens has 21 elements in 15 groups. According to OM System, these include 4 ED elements, 2 HR elements and 2 Super HR elements. The element and group count matches the previous version, and a hands-on report by Jason Odell describes the optical design as unchanged. The maximum aperture is F5.0 at 100mm and F6.3 at 400mm, the smallest aperture is F22, and the diaphragm has 9 circular blades.

Autofocus and handling

The main change over the predecessor is the image stabilizer. The lens has 5-axis Sync IS, which works together with the in-body stabilization of compatible OM System cameras, and OM System quotes up to 7 stops of shutter speed compensation. The minimum focus distance is 1.3 m with a maximum magnification of 0.29x, which equals 0.57x in 35mm terms. The MC-14 and MC-20 teleconverters are supported.

Build and size

The lens weighs 1,125 g without tripod adapter, caps and hood, is 205.6 mm long and 86.4 mm wide, and takes 72 mm filters. OM System lists IPX1 splashproof sealing plus dustproof and freezeproof construction. The front element has a fluorine coating. The tripod foot can be detached while the lens is mounted on the camera, and it is compatible with Arca-Swiss type clamps.

Where it fits

The direct predecessor is the Olympus M.Zuiko Digital ED 100-400mm F5.0-6.3 IS, which has the same 21/15 construction. For even more reach within the system, there is the OM System 150-600mm F5.0-6.3. The Panasonic Leica DG Vario-Elmar 100-400mm F4.0-6.3 II ASPH Power OIS covers the same range with a faster aperture at the short end. If a constant F2.8 over a shorter range is enough, see the OM System M.Zuiko Digital ED 50-200mm F2.8 IS Pro.

Pros and cons

Pros

• Large 200-800mm equivalent range in a compact zoom
• Sync IS with up to 7 stops according to OM System
• Detachable, Arca-Swiss compatible tripod foot
• IPX1 sealing, dustproof and freezeproof

Cons

• Slow maximum aperture of F6.3 at the long end
• Minimum focus distance of 1.3 m
• At 1,125 g, heavy for a Micro Four Thirds lens
• Sealing rating is lower than the IP53 of the 50-200mm F2.8 IS Pro

Verdict

The 100-400mm F5.0-6.3 IS II keeps the proven optical layout of its predecessor and fixes its weak point, the stabilization, while adding better sealing. For wildlife photographers on Micro Four Thirds who want 800mm equivalent, it is the smallest and lightest of the three super-telephoto zooms in the OM System lineup, according to Odell. Those who often shoot in dim light will find F6.3 limiting.