Traduction de Manuel M

Presentation taking from the directory of the Annuaire de la photographie of 1898

Stereoscopic Steno-Jumelle

The characteristic of this stereoscopic Jumelle camera is the extreme reduction of its format and the few place which the various components occupy which make move the multiple combinations to which it gives itself.
The system and construction are identically the same ones as for our models 6.5 x 9 and 9 x 12, no difference exist in the directions for use other than those particular with the stereoscopy. Volume is appreciably the same one as that of certain binoculars 6.5 x 9 which require the volume of the frame twice. The height is similar, since in fact lenses of the same focal distance are adapted there.
We chose the format 8 x 8 because it meets the best conditions. Indeed, the simple cliché provide sufficiently large prints, and the positive ones on glass which one obtains constitute of the cliché of projection of the used format.
With all the stereoscopic cameras which exist, there is always notable part of the images which, not being repeated on each cliché, is sacrificed, since it could not be seen in relief.
Specific measures were taken stereoscopically to see the prints in their entirety. The superiority of this combination is, whatever the sizes of the image which one will want to preserve, according to the spacings desired to be able to take the most interesting parts without being limited.

Our stereoscopic Jumelle camera makes it possible indifferently to use frames containing 2 plates 8 x 8 or others receiving from the plates 8 x 16. For the first case there will be never the disadvantage of developing cliché of different subjects together, as that frequently arrives with the similar cameras.
It goes without saying that one can always make cliché separated by masking one alternatively one of the lenses. This way, one could obtain twenty-four different cliché.
The shuttering guillotine system allows for instantaneous very different speeds. With the back of the lenses, its parts close the mechanism hermetically, which makes impossible the introduction of dust or fragments of glasses.
The focusing is actuated by an extremely simple system of gears which makes it possible the lenses to be moved in parallel, which is almost impossible when all the front of the camera moves.
The operation is appreciably the same one that in the other STENO-JUMELLES. It differs only on the following points:

Focusing: Regulated from the infinite (∞) to 1m50. Make to move in the direction of the arrow the button G until the mark coincides with the number which represents in meters the distance to which is placed the subject.

Viewfinder: It answers for the direct centring to the same conditions as for our other jumelles cameras.
If one wants to centre by reflection, as with the detectives, to get out on the block located close to the needle; the mirror straightens itself with 45°, and, so that it is with height of the lens, one will lengthen the mirror-holder with slide until the end of his way

Frame:  Notches practiced on one of the edges of the frames are used to distinguish the right cliché from the left cliché.
All the amateurs know that the positive tests must be interchanged, i.e. that obtained by the cliché of right-hand side will be stuck on the left side of carton, and that of the left cliché on the right-sided.
As for the spacing to be given to the two prints, it will have to be for the same point of each image of 0m070 (Decision of the Congress). However one can, without much disadvantage, to take it until 0m075.
The framework of this brochure does not allow us to extend more on the manner of getting out the positive ones on paper or glass; we return for that to the many reference books which treat stereoscopy.