Hémisphérique DARLOT, B TE' SGDG 14, r. Chapon Paris n°453
8,65 x 9,6 cm. F=: 40cm. ca.
1864 Convertible lens
f/3,66 F= 19 cm. C+F - ? -F-C C: 10°- 50°
The front element is screwed on at the rear, like a landscape doublet with a 30 cm focal length, using the cap/ diaphragm/ shutter. The cap/ shutter is inserted with pressure. The screwable rear element, painted black, has empty internal threads. The front group also has empty internal threads. These internal threads allowed for the insertion of additional lenses in order to vary the focal length. The central diaphragm is a Waterhouse type.
A short excerpt from "Darlot"
Pag 120…Alphonse Darlot (3/9/1828-5/10/1895) started his training at the age of twelve as an optician alongside Lerebours; later, he trained in Jamin's laboratory. He opened his own laboratory in Paris in place Dauphine 2-4 (15). In 1860 he partnered with Jamin, and for a period of three years, until 1862, both names appear on the lens barrels. In 1863 the brand name was “Darlot Paris” and in 1864 "Anc. M.Jamin DARLOT Opt.n Succ.r". In 1866 the Hémisphérique appeared with the engraving "DARLOT, BTE' SGDG". After the separation with Jamin, the seat of the company remained in rue Chapon 14 in Paris. It is likely that Jamin gave up ownership, as his name no longer appears on the lenses from that point on, and also because the company did not change address. In 1877 the company moved to boulevard Voltaire 125. Darlot was highly esteemed by his contemporaries: in 1867 he was given a silver medal at the International Expo of Paris, and in 1892 he was decorated with the Legion of Honor (1). Only after years of activity did the brand pass on to L. Turillon, his successor, either in 1893 (3) or in 1895 (1). Turillon appears to be the builder of the artist lens of Pulligny. In this period, the company store was located at Rue Lafayette 99, Paris (4). Darlot, in addition to having been a successful and shrewd businessman, was also the builder of various types of photographic lenses, such as centralizing cones, Petzval lenses, landscape lenses, and the rectilinear Hémisphérique and Hémisphérique Rapide. We can conclude this, since in 1863, after succeeding Jamin, there was a jump in the production of centralizing cones from 4,500 pieces….(continues)