Leica's original screw-mount short tele — the 90mm f/4 Elmar, rangefinder portrait glass.
The Elmar 90mm f/4, engraved in centimetres as 9cm, was the original short telephoto for the screw-mount Leica system, dating from the early 1930s. It filled the portrait and short-tele slot in the Leica line and remained in the catalogue in various forms for decades on the 39mm Leica Thread Mount.
This is a manual-focus, rangefinder-coupled Leica Thread Mount lens with a 90mm focal length and a maximum aperture of f/4. Early examples are long, nickel or chrome brass barrels; later runs were shorter. Confirm the barrel style, filter thread and whether a given example is coated before relying on those details.
A 90mm on a rangefinder is a classic portrait and short-telephoto focal length, giving flattering perspective and background separation. The f/4 Elmar is a moderate-speed lens that stops down cleanly, and early uncoated examples show the softer contrast typical of pre-war Leitz glass.
On the used market this is collector-driven, with early long-barrel and nickel versions commanding more than common chrome examples. Check for haze and cleaning marks across the elements, coating wear on later coated samples, and element separation; confirm smooth focus, dry aperture blades and correct rangefinder coupling. It adapts to Leica M with a 39-to-M adapter and to mirrorless with an L39 adapter.