The name Elmar is used by Leica to designate camera lenses of four elements that have a maximum aperture of f/3.98 or f/4.0.
The Elmar lenses originally had a maximum aperture of f/3.5. These lenses were derived from a 50 mm f/3.5 Elmax lens first produced in 1925. The name is a combination of Ernst Leitz and Max Berak.
Elmar lenses variously has a maximum f-number of f/2.8 or f/3.4 or f/3.8 or f/4. Currently the Elmar lenses have a maximum aperture of f/3.8 or f/4, as in the Elmar-M 24 mm f/3.8 and Tri-Elmar-M 16-18-21 mm f/4. The name Elmar is sometimes combined with: Super, Tele, APO, Macro or Vario.
Elmar lenses are comparatively slow. As a result they tend to be smaller and lighter than faster lenses of the same focal length.