NIKON AI NIKKOR 135mm f/2

US 4,062,630, Example V — Sei Matsui

6 elements / 4 groups
Ai / Ai-S Nikkor 135mm f/2 (1977–2005)
f = 135 mm (patent f = 100 mm × 1.35)
Tele-Sonnar / Ernostar variant

Focus Mechanism

Unit focusing — entire optical assembly translates forward; only BFD changes (1.3 m close state calculated, not published)

Optical Elements (6 physical)

ElementTypeGlass
L1Positive MeniscusS-LAM3 (OHARA)
L2Negative Meniscus626391 — barium flint (patent coordinate; vendor unresolved)
L3Positive MeniscusOHARA S-BAL35 / HOYA BACD5 (589/612)
L4Plano-Convex PositiveFD3 (HOYA catalog-equivalent; production supplier unspecified)
L5Biconcave NegativeHOYA E-FD1 / Schott SF1 (717/295)
L6Positive MeniscusHOYA E-FD1 / Schott SF1 (717/295)