Yongnuo YN 42.5mm f/1.7 M II Lens for Micro Four Thirds

The Yongnuo YN 42.5mm f/1.7 M II is an affordable portrait-length prime lens designed for Micro Four Thirds mirrorless cameras, delivering an 85mm full-frame-equivalent field of view. It’s aimed at photographers who want a fast, budget-friendly prime for portraiture, low-light shooting, and selective-focus work on Olympus/OM System and Panasonic Micro Four Thirds bodies.

Optically, the lens offers a 42.5mm focal length with a maximum aperture of f/1.7, allowing for strong background blur and meaningful control over depth of field, along with solid low-light performance for a lens in this price tier. The 9-element, 8-group optical construction includes two ultra-low dispersion (ED) elements along with multi-layer coating across all optical surfaces, helping suppress backlit ghosting and glare while maintaining contrast. A 7-blade diaphragm contributes to smooth, pleasing bokeh, a key draw for this focal length and aperture combination.

Autofocus is handled by Yongnuo’s STM (stepping motor) system, delivering smooth, quiet, and accurate autofocus, an improvement over the original version of this lens, along with full-time manual focus override and a dedicated AF/MF switch on the barrel. The lens has a minimum focusing distance of approximately 0.30m, yielding a maximum magnification of about 0.15x, giving some flexibility for closer subjects in addition to standard portrait-distance shooting.

Build quality includes a lightweight housing with a durable, chrome-plated metal mount resistant to corrosion, along with gold-plated contacts for improved signal transmission. The lens weighs approximately 135-146g and measures about 61.6 x 55.4mm, and accepts a 52mm filter thread.

As a Micro Four Thirds-specific lens, the Yongnuo YN 42.5mm f/1.7 M II is designed exclusively for Micro Four Thirds mirrorless cameras from Olympus/OM System, Panasonic, and other Micro Four Thirds alliance manufacturers.

Key Features
– 42.5mm f/1.7 portrait-length prime lens for Micro Four Thirds
– 85mm full-frame-equivalent field of view
– 9 elements in 8 groups, including 2 ED elements
– Multi-layer lens coating
– STM stepping motor autofocus with AF/MF switch and full-time manual override
– 7-blade diaphragm
– Minimum focusing distance of approximately 0.30m
– Maximum magnification of approximately 0.15x
– Chrome-plated metal mount with gold-plated contacts
– 52mm filter thread
– Lightweight design (approximately 135-146g)
– Compatible with Micro Four Thirds mirrorless cameras (Olympus/OM System, Panasonic, and alliance partners)