/fəʊˈkɒmətə/, U.S. /foʊˈkɑmətər/. focimetern.
/fəʊˈsɪmᵻtə/, U.S. /foʊˈsɪmᵻdər//fəʊˈkɒmətə/, U.S. /foʊˈkɑmətər/. Optics and Photography.
An instrument for finding the focal length of a lens; spec. an instrument for finding the chemical focus of a lens, esp. in relation to the visual focus. Cf. chemical focus n. at chemical adj. and n. Compounds 3.
ΘΚΠ
society > leisure > the arts > visual arts > photography > camera > parts and accessories of camera > [noun] > lens > instrument for finding chemical focus
focimeter1828
1828 G. Dakin in Philos. Mag. 2nd Ser. 4 431 I strongly suspect that the focal distances of lenses are generally underrated by opticians. To prove mine, I made what may be called a Focimeter.
1851 R. Hunt Photography xv. 215 Mr. Claudet has also devised a very ingenious instrument for focusing, which he calls his Focimeter.
1891 Proc. Royal Soc. 1890–91 49 227 These principles are embodied in an instrument described in the paper, and called a focometer.
1935 Camera June 410/1 As we all know, chemical and visual focus are not the same thing. In order to test this quality of a lens, an instrument called a ‘focimeter’ is used.
1969 Jrnl. Brit. Astron. Assoc. 79 341 Mr Dall said that many commercial eyepieces had their focal lengths wrongly given; he used a focometer, but this was a complex device.
2007 European Lenses & Technol. Oct. 36 A tint tank, hand edger, focimeter, frame heater and all the commonly used tooling and consumables, are included in the..price.
This entry has been updated (OED Third Edition, September 2016; most recently modified version published online March 2022).
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n.1828