CARL ZEISS BIOGON 21mm f/4.5 — Optical Cross-Section & Ray Tracing

Home / Lenses / Carl Zeiss Oberkochen / CARL ZEISS BIOGON 21mm f/4.5CARL ZEISS BIOGON 21mm f/4.5US 2,721,499↗, Example 2 — Ludwig Bertele
8 ELEMENTS / 5 GROUPS
f = 21.0 mm (design)
F/4.5
2ω ≈ 91.4°
ALL SPHERICAL
Focus MechanismUnit focus — entire lens translates axially.
Optical Elements (8 physical)ElementTypeGlass
L1Negative MeniscusPC1 (HOYA catalog equivalent; production supplier unspecified; patent 504667)
L2Negative MeniscusFK5 fluor crown class (487/703; catalog equivalent, production supplier unspecified)
L3Negative Meniscus721503 LaK10 class; J-LAK10 catalog spectral proxy (production supplier unspecified)
L4Biconvex PositiveK-SK7 (Sumita)
L5Biconcave Negative570575 — BaK-type barium crown (no exact catalog match)
L6Biconvex Positive625533 — SSK-type dense crown (no exact catalog match)
L7Negative MeniscusSF1 dense flint (720/293)
L8Negative MeniscusLAC6 (HOYA) class (642581 lanthanum crown, LaK6 type; Δnd +0.0005, Δνd −0.14; equivalent)

Element	Type	Glass
L1	Negative Meniscus	PC1 (HOYA catalog equivalent; production supplier unspecified; patent 504667)
L2	Negative Meniscus	FK5 fluor crown class (487/703; catalog equivalent, production supplier unspecified)
L3	Negative Meniscus	721503 LaK10 class; J-LAK10 catalog spectral proxy (production supplier unspecified)
L4	Biconvex Positive	K-SK7 (Sumita)
L5	Biconcave Negative	570575 — BaK-type barium crown (no exact catalog match)
L6	Biconvex Positive	625533 — SSK-type dense crown (no exact catalog match)
L7	Negative Meniscus	SF1 dense flint (720/293)
L8	Negative Meniscus	LAC6 (HOYA) class (642581 lanthanum crown, LaK6 type; Δnd +0.0005, Δνd −0.14; equivalent)