|Advertisement for the Alsaflex, in Réalités, April 1955.|
scanned by busy.pochi (Image rights)
The Alsaflex is an innovative and compact SLR camera, made in the early 1950s by Alsaphot. It was designed by Lucien Dodin,  who also held patents relating to the invention of the split prism and micro-prism focusing aids widely-used in SLR cameras, and to their incorporation in SLR focusing screens. The camera makes images 24 mm square on standard 135 film; a panel in the back of the camera is also removable to allow a single-exposure film-holder to be fitted.
The camera is compact for an SLR, largely because it does not have a pentaprism; the image-forming light is instead reflected by a mirror and two prisms mounted within the camera body, and is finally presented, upright and correct right-to-left, in the viewfinder.
The lens is interchangeable (though both the camera and lenses for it are rare), with a bayonet mount in a lens-plate which can be slid upwards (front rise, for perspective control). The shutter is a metal blade, in the form of a fan; a disc with a large sector cut out, rather like the sector shutter in many box cameras, but giving speeds from 1 to 1/2000 second, plus 'B'. The shutter speed control, on the front of the camera, has slow- and fast-speed dials, concentric and one on top of the other. The shutter is synchronised for bulb and electronic flash (at all speeds, according to the notes at Novacon).
The Dudragne is a special, much simpler model of the Alsaflex, without a horizontal viewfinder eyepiece, made to be used with a retinograph (instrument for examining the retina of the eye) made by Dudragne; In this model, the image is simply reflected upwards to a vertical viewfinder by a single mirror. All but one of the examples cited is without a lens or lens-plate, and it seems likely that these were not needed to use the camera with the retinograph. The shutter has only one instantaneous shutter speed.
- ↑ 1.0 1.1 Alsaflex serial no. 176, with Boyer Saphir 40 mm f/3.5 lens, sold at the 24th Westlicht Photographica Auction, on 23 November 2013; several excellent pictures of the camera. The camera's shutter speed control is marked to 1/2000 second. An SOM Berthiot Flor 50 mm f/2.8 with the Alsaflex bayonet mount was also sold at the same auction.
- ↑ Alsaflex at Sylvain Halgand's Collection Appareils.
- ↑ 3.0 3.1 Alsaflex at Novacon.
- ↑ 4.0 4.1 Alsaflex 'Dudragne' serial no 414756, at Collection Appareils; the notes state that the last two digits of the serial number give the year of manufacture.
- ↑ Alsaflex 'Dudragne' serial no. 410256,0, sold with Boyer Saphir 50 mm f/2.8 lens, sold at the ninth Westlicht auction, in May 2006.
- ↑ Alsaflex 'Dudragne' serial no. 440 55, sold at the auction Photographica 20 mit Fernoptik + Wissenschaftlichen Instrumenten (Photographica 20 with tele-lenses and scientific instruments) on 27 May 2012, by Rahn AG.
- Alsaphot page at Gérard Langlois' site, with a link to a picture of the Alsaflex