His works on time-lapse photography allows him to meet another inventor-engineer : Charles Dessoudeix. This last one is a specialist in horology. Charles Dessoudeix had a small factory that he sold to Charles Bazin.

Its novelty was relying on its capability to easily produce both 6 x 6 cm stereoscopic views and 6 x 13 cm panoramic views.

Other cameras were also presenting this characteristic, such as the jumelle cameras based on a horizontal decentration. The beauty of the solution found by Lucien Leroy to easily switch from one format to the other has placed this camera much ahead of all its opponents.

Lucien Leroy's idea was to locate the shutter behind the lenses. The platform supporting the right lens can rotate on its axis in order to move this lens in to a central position. When using the panoramic mode, the lens not used had to be closed up with a lens cap.

Another interesting characteristic is that the hole of each shutter has a surface which is twice bigger than the one of the rear lens. This is increasing by 50% the quantity of light arriving on the plate 6 x 13 cm when using the panoramic mode, ensuring a better luminosity of the pictures.

Regarding optical characteristics, the Stereo-panoramique was offered with different lenses from several famous manufacturers. All these lenses have a focal distance between 80 and 82 mm; this was a good compromise for both proposed formats.

In 1914, the proposed lenses (all equiped with an iris) was the following:

It is probable that starting from 1914, the German lenses made by Zeiss or Goerz were no longer mounted on Leroy cameras.
For information, the camera presented here has been initially purchased with Krauss Protar lenses but these ones have been replaced later on by Lacour-Berthiot lenses, much more performing.

5 shutter speeds (+ pose) are available using a selector located on the top right of the front face of the camera.
Position 1 gives 1/10 second, 2 = 1/25 second, 3 = 1/45 second, 4 = 1/60 second and 5 = 1/75 second.