Not a zoom, this lens offers three discrete focal lengths that each click-stop into place. Among its other unusual amenities: red barrel threading that alerts you to screw on the hood.
Standout Spec: Three sharp lenses in one housing.
Lens Test: Leica Tri-Elmar-M 16-18-21mm f/4 ASPH
Leica Tri-Elmar-M 16–18–21mm f/4 ASPH
Leica 90MM F/4 Macro-Elmar M
Leica Noctilux-M 50mm f/0.95 ASPH
Leica Summicron-M 50mm f/2