Elements
7
Spec Notes
Aperture scale from Kodak's instruction book: f/1.9, 2.8, 4, 5.6, 8, 11, 16, 22. Filter Series VI via Kodak Adapter Ring No. 24. Min focus 3.5 ft normal, red close-up to 18 in (46 cm). CAMEROSITY: this is the ONLY Ektra focal length with confirmed two-letter date-code examples — ER462 and ER275 (1945) on the two Ektra II prototypes, EO846 (1946), and RY142 (1950) on a Television Ektanon 90mm. bnphoto states the code sits on the part of the barrel that fits into the camera mount. APPLICATION WAS NOT UNIVERSAL: the Science Museum Group's accessioned Ektra carries a 50mm f/3.5 numbered simply 580, with no prefix. Absence of a prefix therefore dates nothing. ELEMENTS = 7 is the ONLY element count in this slice recorded as a value, on two independent secondary sources agreeing (a detailed review of a measured example, and an encyclopedia entry) — still not a Kodak figure. GROUPS NOT RECORDED: the "4 groups" figure is single-source. WEIGHT NOT RECORDED: 308 g comes from one reviewer weighing one example, which is a measurement rather than a published spec — the same call made for the Retina-Heligon in Slice 1. NAME COLLISION — GUARD: a Kodak Cine Ektar 50mm f/1.9 exists in C-mount for 16mm cine. Different mount, near-identical name. 1941 list price $125.00, the same as the 35mm.
Max Aperture
f/1.9
Min Aperture
f/22
Min Focus Distance
46cm
Filter Series
VI
Alternate Names
—
Introduced
1941
Focal Length (Max)
50mm
Focal Length (Min)
50mm