PENTAX DA 70mm f/2.4 Limited

US 7,542,219 B2 Embodiment 1 — Hoya / Saori

6 elements / 5 groups
70 mm (scaled from patent f=67.74)
f/2.4 nominal; patent FNO 1:2.5
23° production field / 25.2° patent field
All-spherical modified Gauss

Focus Mechanism

Unit focus; the complete optical cell translates forward, modeled by increasing back focus from infinity to 0.7 m.

Optical Elements (6)

ElementTypeGlass
L1Positive MeniscusS-LAL14 / LAC14 class lanthanum crown (698555 patent melt)
L2Positive MeniscusUnmatched lanthanum crown (682575; no exact current public catalog match)
L3Negative MeniscusUnmatched dense flint (794255; SF/S-TIH class)
L4Negative MeniscusUnmatched barium flint (676440; BaF/BaSF class)
L5Positive MeniscusBaK2-class light barium crown (544601; soft catalog match)
L6Biconvex PositiveS-LAM66 (OHARA) / N-LASF45 (Schott), 801350

Analysis

Detailed analysis available in the interactive viewer above.