Metrogon is a high resolution, low-distortion, extra-wide field (90 degree field of view ) photographic lens design, popularized by Bausch and Lomb . Variations of this design were used extensively by the US military for aerial photography , fitted to the T-11 and other aerial cameras.
4-522: The most common Metrogon lenses have a f number of 6.3 and a focal length of 6 inches. The company name (Bausch and Lomb) and the US Patent number (2031792) are prominently inscribed on the front of the lens barrel. However, this patent is for a family of symmetric wide-angle lenses designed by Robert Richter of Carl Zeiss AG , which was filed in 1934 and sold by Zeiss as the Topogon . For this reason, it
8-486: A single photograph. By 1944, the military had charted 3,000,000 sq mi (7,800,000 km) in a single year using the tri- Metrogon , a triple aerial camera system fitted to the noses of aircraft including the P-38 Lightning and B-25 Mitchell . In 1943, Bausch and Lomb was granted an independent patent for a similar lens design with 5 elements and the same f /6.3 maximum aperture, showing less distortion than
12-578: Is believed the Metrogon lenses marked with this patent are a licensed version of the popular and very similar (if not identical) Topogon design. An aerial camera fitted with a Metrogon lens deployed by the United States Army Air Corps was featured in a 1941 article in Popular Science , which noted the lens gave the camera a 93° field of view, doubling the area that could be captured in
16-539: The lens in the Carl Zeiss patent. The Bausch and Lomb patent also compares the distortion of their design favorably to a similar 5 element lens, patented in 1938, which has a slightly wider maximum f-number of f /5.6 . It is not certain whether Bausch and Lomb incorporated their own design instead of the Zeiss design when producing Metrogon lenses after 1943. The introduction of faster lenses with equivalent coverage including
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