Stéréoscope elliptique, Short Focus, Oval Lenses

This stere­o­scope is attrib­uted to Fer­di­nand Dri­er, an opti­cal instru­ment mak­er liv­ing at 83 rue du Marais-Saint-Mar­tin in Paris. On 17 Decem­ber 1856, he filed patent FR 30,198 for an ellip­ti­cal stere­o­scope. His inven­tion con­sist­ed of replac­ing cir­cu­lar eye­pieces with oval or ellip­ti­cal ones, which he con­sid­ered bet­ter suit­ed to accom­mo­dat­ing dif­fer­ent visu­al focal points. He used prisms for their diverg­ing effect, while adopt­ing an oval shape to enlarge the field of view through the stereoscope’s eyepieces.
In April 1857, Fer­di­nand Dri­er filed an addi­tion to his patent to sim­pli­fy the man­u­fac­ture of stere­o­scope eye­pieces. It pro­posed using com­mer­cial­ly avail­able spec­ta­cle lens­es, which nat­u­ral­ly have a lentic­u­lar shape and thus pro­vide the inclined or pris­mat­ic form suit­ed to the stereo­scop­ic effect. No stere­o­scope of this lat­ter type has been observed.

(from: Moulin­ier et al. His­toires de vision­neuses stéréo­scopiques français­es. Limo­ges, 2025, p. 210. Author’s translation.)

“D.P.” may stand for “Dri­er, Paris,” though no con­clu­sive evi­dence has been found to con­firm this read­ing. Oth­er stere­o­scopes stamped “F.D.” have been ten­ta­tive­ly attrib­uted to Fer­di­nand Dri­er. A near-iden­ti­cal mod­el fit­ted with rec­tan­gu­lar prism lens­es is illus­trat­ed here.