MAMIYA SEKOR AF 55mm f/2.8

JP 1997-297263 A — Hisataro Shimada

7 ELEMENTS / 6 GROUPS
f = 54.99997 mm (DESIGN)
F/2.8
2ω = 64°
ALL-SPHERICAL

Focus Mechanism

NO_INTERNAL_RECONSTRUCTION — manufacturer literature describes floating-element focusing to 0.45 m, but JP 1997-297263 Example 1 publishes no focus-motion data. Only the published infinity-like state is modeled.

Optical Elements (7 physical)

ElementTypeGlass
L1Negative MeniscusBSL7 (legacy OHARA coordinate match; 516642)
L2Biconvex PositiveLAL8 (legacy OHARA coordinate match; 713538)
L3Negative MeniscusBAM8 (legacy OHARA coordinate match; 624471)
L4Positive MeniscusLAH52 (legacy OHARA coordinate match; 800422)
L5Biconcave NegativeBPH50 (legacy OHARA coordinate match; 740317)
L6Positive MeniscusFPL51 (legacy OHARA coordinate match; 497816)
L7Positive MeniscusLAL61 (legacy OHARA coordinate match; 741527)