Although more costly
than the Nikon Z 40mm f/2 FX format lens on test, this Yongnuo is more akin to the rather pricier Nikon Z 50mm f/1.8 S in the group. It boasts high-end features with fast and highly accurate stepping motor-based autofocus, an easy-access AF/MF switch and a nippy aperture rating that matches the pricier Nikon.
But the Yongnuo goes one better in terms of handling, adding a duplicated pair of customizable L-Fn buttons. These are typically used for AF-hold but you can assign other functions. The only catch is that the buttons are wired up in parallel, so you can’t assign different functions to each one. However, the design makes accessibility of the buttons feel equally natural with both landscape and portraitorientation shots. Autofocus is driven by the now-usual linear stepping motor. Also typically, the electronically coupled focus control ring can be assigned to alternative functions when using the lens in autofocus mode. Build quality is good with a weather-sealed metal mounting plate, while the optical layout includes a low-dispersion element and nano-structure multi-coatings. The USB port for applying firmware updates sits beneath a weather-seal cover.