The Leica Super-Elmar-M 21mm f/3.4 ASPH is a premium super-wide-angle prime lens for M-mount rangefinder cameras, known for its exceptional sharpness, high contrast, and compact design. It is widely used for architectural, landscape, and street photography due to its precise optical correction and minimal distortion.
Key Specifications
Aperture Range: f/3.4 to f/16.
Angle of View: 91° diagonal.
Optical Design: 8 elements in 7 groups, including one double-sided aspherical element and four anomalous partial dispersion elements to minimize aberrations.
Minimum Focus: 0.7m (2.3'), with a working range of 0.5m to infinity.
Dimensions & Weight: Measures approximately 43mm in length and weighs 279g (black anodized version).
Filter Size: E46 (46mm).
Features: 6-bit coding for digital M cameras and a screw-on rectangular metal lens hood.
Optical Performance
The lens delivers outstanding detail even at its maximum f/3.4 aperture, with sharpness maintained from corner to corner. It is highly resistant to flare and ghosting, making it effective for backlit shots. While it exhibits some natural vignetting (approx. 2.1 stops at f/3.4), this is reduced by stopping down to f/5.6.