TTArtisan — manual 21mm f/1.5 fast full-frame wide-angle prime, multiple mirrorless mounts
The 21mm f/1.5 is a full-frame manual wide-angle from TTArtisan, one of the company's earliest fast primes and marketed as one of the smallest and lightest full-frame wide lenses available for mirrorless cameras. It was tested early on both Sony and Leica M rangefinder bodies via adapters.
Construction is 13 elements in 11 groups, manually focused through an all-metal barrel with a 72mm filter thread and a 10-blade aperture. Weight runs approximately 422-458g depending on mount, and the lens ships with a tulip-shaped hood and round filter holder given its bulbous front element.
At f/1.5 the 21mm focal length gives a genuinely wide field of view with meaningful subject separation, unusual for this focal length at this speed and price. Corner softness and vignetting are pronounced wide open, tightening up by f/4, typical of fast retrofocus wide-angle designs at this cost.
It was sold in Sony E, Nikon Z, Canon RF and L-mount versions, plus a dedicated rangefinder-coupled Leica M edition; the L-mount variant is now discontinued. Used buyers should check the bulbous front element carefully for scratches, since its curved shape makes standard flat filters and caps impractical.