Voigtlander's compact modern wide — the Cosina-made Color-Skopar 21mm f/4 in Leica Thread Mount.
The Color-Skopar 21mm f/4 is a modern Cosina-made Voigtlander wide-angle from the late-1990s Bessa revival, released in 1999. It is a contemporary manual-focus optic in Leica Thread Mount rather than a vintage lens, sold as a compact wide-angle option for screw-mount and adapted rangefinder bodies.
It is a manual-focus rangefinder lens with a 21mm focal length and a maximum aperture of f/4. The design is notably compact for its coverage, and it uses an accessory viewfinder for framing since most rangefinder bodies do not show a 21mm field. Depth of field is deep at this focal length, which suits scale focusing.
At 21mm it delivers a wide, mostly rectilinear view that suits landscapes, interiors and street scenes where you want context around the subject. Rendering is even and contrasty for a compact wide, and stopping down to f/8 or so gives broad depth of field and tidy corners.
As a newer Cosina-Voigtlander design, used examples are usually in good order and reasonably easy to find; the priorities are clean glass, smooth focus and a crisp aperture rather than age-related faults. It mounts on Leica M bodies via an LTM adapter and works well on mirrorless cameras, where a matching external finder or the camera screen handles framing.