PENTAX HD D FA645 35mm f/3.5 AL [IF]

US 2001/0007512 A1 — Takayuki Sensui

10 PHYSICAL ELEMENTS / 8 PATENT GROUPS
PATENT DESIGN f = 36.000 mm
MODELED f/3.6
2ω = 89.6° AT y = 34.85 mm
2 ASPHERICAL SURFACES
PUBLISHED REAR-FOCUS ENDPOINT m = 0.200

Focus Mechanism

PUBLISHED rear focus: G2 (13–19A, including STO) translates 7.810 mm objectward. The patent endpoint is m=0.200 and solves to 0.336052 m object-to-image distance; the marketed 0.3 m / 0.25x values are not forced onto this prescription.

Optical Elements (10 physical; 11 modeled media)

ElementTypeGlass
L1Negative Meniscus773496 — lanthanum-flint class (vendor unresolved)
L2gNegative Meniscus729547 — lanthanum-crown class (vendor unresolved)
L2rNegative Meniscus (1× Asph)Unmatched (synthetic resin; patent nd=1.52700, νd=43.7)
L3Biconvex Positive755275 — dense-flint class (vendor unresolved)
L4Positive Meniscus517524 — crown-flint class (vendor unresolved)
L5Negative Meniscus804466 — lanthanum-flint class (vendor unresolved)
L6Positive Meniscus518590 — crown class (vendor unresolved)
L7Biconvex Positive487702 — fluor-crown class (vendor unresolved)
L8Negative Meniscus847238 — special dense-flint class (vendor unresolved)
L9Negative Meniscus847238 — special dense-flint class (vendor unresolved)
L10Biconvex Positive (1× Asph)Unmatched (barium-crown vicinity; no exact public-catalog match)