Ross London 5" (127mm) Wide Angle Xpres F4

 WWII RAF aerial reconnaissance lens. Ross London 5” (127mm) Wide Angle Xpres f/4 E.M.I. (Extra Military Issue) variant, higher-quality military model for Air Ministry/RAF. Serial 148065 indicates 1940s wartime production. Mounted in aerial cameras on aircraft (e.g., torpedo bombers) for surveillance and combat documentation.

With Rack & Pinion focusing adapter