Bloch Le Physiographe
As camera makers, Edmund and Leon Bloch seem to have been in love with "detective" cameras. The late nineteenth century saw a profusion of hidden or candid cameras, which may broadly be categorized as detective cameras, although odds are few were used for actual detective work. Most likely found their way onto the beaches of southern France in the hands of married men looking for a little excitement. The Bloch brothers produced cameras in the form of a book, a cravate, a briefcase, a monocular, and like this example, a pair of binoculars. Was anyone ever fooled by one these devices? Who knows. Le Physiograph was patented in the late 1890s and soldiered on in production until after WWI.
Camera controls are located between the objective lenses. The one on the left is fake, and is used as a handle for the plate changing magazine. The right objective looked through a 90 degree finder located in the black rim. Because the natural tendency is to hold a binocular with both hands, I could see many images being ruined by a hand in front of one of the lenses. The difficulty of using the 90 degree finder likely also lead to many angled images. According to McKeowns, early examples were in 5 x 12 format. Later examples, like this one, are in the ubiquitous 45 x 107.