VOIGTLÄNDER APO-LANTHAR 50mm f/2.0 Aspherical

JP 2021-043376 A — Yasuyuki Sugano

10 ELEMENTS / 8 GROUPS
f ≈ 49.3 mm
F/1.93
2ω ≈ 47.4°
4 ASPHERICAL SURFACES
2 PATENT-LISTED APD ELEMENTS

Focus Mechanism

Patent F36 floating focus: front group, Jb, and Ja+LE move 8.94, 8.54, and 5.53 mm toward the object. Close endpoint is 0.455 m from the image plane (370 mm from surface 1). Intermediate motion is interpolated.

Optical Elements (10 physical)

ElementTypeGlass
LFBiconcave NegativeUnmatched (patent glass; supplier unspecified)
LfaPos. Meniscus (2× Asph)Unmatched (patent nd=1.85249, νd=42.08; supplier unspecified)
LfbBiconvex PositiveS-FPL51 / N-PK52A (catalog-compatible equivalents; supplier unspecified)
LfcBiconvex PositiveFCD505 (catalog-compatible model; supplier unspecified)
LfdNegative MeniscusUnmatched (patent glass; supplier unspecified)
LrdBiconcave NegativeUnmatched (patent nd=1.70269, νd=34.87; partial dispersion unspecified)
LrcBiconvex PositiveUnmatched (patent nd=1.79334, νd=47.18; supplier unspecified)
LrbBiconvex PositiveS-LAH65V (catalog-compatible model; supplier unspecified)
LraBiconcave NegativeUnmatched (patent nd=1.55362, νd=45.38; supplier unspecified)
LENeg. Meniscus (2× Asph)S-BSL7 / N-BK7 (catalog-compatible equivalents; supplier unspecified)