Leudi
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| Leudi 3 meter image by Steve Harwood (Image rights) |
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| Leudi meters and Durex meter image by Simon Spaans (Image rights) |
The Leudi is a simple extinction meter, patented by Alois Leber in 1933.[1] The device consists of a plastic housing surrounding a rectangular slot, in which is mounted an optical wedge (a strip of translucent material, whose translucency varies continuously from one end to the other). On this is printed a series of marks, for example numbers 1 to 6 or 8. The user looks through the slot, and reads the last readily-visible number under the prevailing light. An interpretation table is wrapped around the outside of the housing, and a clear plastic sleeve wrapped over that allows adjustment for film speed (or perhaps to allow for a filter). This table translates the simple number from the optical wedge into exposure settings given the situation (indoor/outdoor, weather etc.) and film speed.
The Leudi was made by Mimosa Corp. for the USA at least into the 1940s, and probably by Pless in Austria for Europe. In the UK, the meter was sold as the Lite (second from right at the bottom in the picture).
Before 1942 a rather similar product was made by Durex.
Leber, an Austrian living in Vienna, also patented slightly more sophisticated light meters.[2]
Notes
- ↑ Austrian Patent 143003, Optischer Belichtungsmesser, filed 9 December 1933 and granted to Alois Leber 10 October 1935. Equivalent French Patent 783838, Photomètre optique and British Patent 444105, Optical exposure meter have diagrams which make clear just how simple the meter is. All at Espacenet, the patent search facility of the European Patent Office.
- ↑ Patents granted to Alois Leber between 1932 and '39.
