Pair of Brass Long Lenses for 19th century Bi-unial Lantern Slide Projector

by

C.B. Kleine / Bausch & Lomb

they measure 7.5" high by 3.25 wide

Maker: C.B. Kleine (Kleine Optical Co.) was a prominent distributor and manufacturer of optical projection equipment, with historical roots spanning Chicago, New York, and Paris.

Configuration: A "bi-unial" system features two aligned optical lenses stacked vertically, requiring a precisely matched pair of focal lengths and matched optical performance to ensure projected images aligned seamlessly on screen. 

Design: Typically constructed with heavy brass barrels, rack-and-pinion or slip-tube focusing, and dual achromatic or plano-convex elements suited for lantern slides

Rarity: Matched pairs are significantly harder to find intact today than single loose projection lenses, as pairs often became separated when projectors were dismantled.

Modern Adaptation: Contemporary photographers and filmmakers occasionally source antique magic lantern brass lenses to adapt them onto modern mirrorless or large-format digital cameras for soft, dreamy, "lo-fi" vintage aesthetics with characteristic chromatic aberration and lens flare