YI Xiaoyi 42.5mm f/1.8 Review

The YI Xiaoyi 42.5mm f/1.8 is a fast portrait-length prime for Micro Four Thirds systems. At 85mm equivalent field of view, it sits squarely in the classic portrait focal length with an aperture wide enough for shallow depth of field and low-light work. YI, known primarily for action cameras and consumer electronics, entered the lens market with this relatively affordable option aimed at MFT shooters looking for a compact portrait solution without the price tag of premium glass from Olympus or Panasonic.

The lens competes in a segment crowded with strong alternatives, including the Panasonic 42.5mm f/1.7 and Olympus 45mm f/1.8, both of which have established reputations for optical quality and autofocus performance. Without widespread user feedback, the Xiaoyi remains a more obscure choice in the MFT ecosystem, though its fast aperture and compact form factor align with the strengths of the format.