LEICA SUMMICRON-C 40mm f/2

DE 2 222 892 A1, Example 3 — Georg Knetsch, Hermann Desch, Heinz Marquardt, Walter Watz

6 ELEMENTS / 4 GROUPS
f = 39.9987 mm (DESIGN)
f/2
2ω = 56.8°
ALL-SPHERICAL

Focus Mechanism

Not modeled — production helical focus reaches 0.8 m, but the patent supplies only the nominal prescription; no finite-focus internal spacing is modeled.

Optical Elements (6 physical)

ElementTypeGlass
L1Positive MeniscusUnmatched (native e-line ne=1.81527, nu_e=45.06; supplier unresolved)
L2Positive MeniscusUnmatched (native e-line ne=1.81527, nu_e=45.06; supplier unresolved)
L3Negative MeniscusSF56A (coordinate-compatible spectral proxy; supplier unconfirmed)
L4Negative MeniscusS-TIM6 (coordinate-compatible spectral proxy; supplier unconfirmed)
L5Positive MeniscusUnmatched (native e-line ne=1.69232, nu_e=49.18; supplier unresolved)
L6Positive MeniscusN-LAK21 (coordinate-compatible spectral proxy; supplier unconfirmed)