Jamin & Darlot Centralizing Cones 'a paysage(petzval)' and 'portrait' lens
 in 1860  focal 10 inch

Lens Data

Lens Unit

Lens Photo

レンズ構成 :
製造番号 : 4093

Lens composition
  : Portrait = Petzval type
   Landscape = Remove optical group from Cone,
                    mount the lens backwards, and turn the
                    front group opposite side.
Serial number : 4093

Lens Impression

ダルロー(Alphonse Darlot 1828-1895)のビジネスを飛躍させた「円錐形の」銘レンズといえます。
ただし、設計はダルローの師匠でもあり、ビジネスパートナーでもあったジャマン(Jean Theodore Jamin ????-1867)です。

従いまして、この円錐形レンズはそれまではJAMINの刻印だけしたが、1860年以降は、JAMIN & DARLOTとなりました。


This Centralizing Cone lens is a remarkable lens which jump Alphonse Darlot's business.
Tne Inventor of this lens was Jean Theodore Jamin who is the employee and later business partner of Darlot.
Its unique shape is for reducing internal reflection of light, and I think it is effective, however I cannot imagine why this type of lens did not become popular in later lens compositions.

Darlot started his carrier at Lerebours and later trained in Jamin's laboratory. In 1860 he started his own business and made partnership with Jamin.
So, its engraved figure until partnership was only JAMIN and changed into JAMIN & DARLOT after 1860.
He was talented in business field,, so hte production of centralizing cone lens increased remarkably which was 4,500 between 1855-1860 had  changed into 23,346 in 1864 one year.

I bought this lens very cheap becauset the bar to control rack and pinion. was lost.

 (ref) Corrado D'Agostini .'Photographic lenses of the 1800's in france'

  Photos with Darlot Centralizing Cone lens
at my home garden


These photos are taken with Pentax 6x7 Camera.
The center focus area shows rather sharp with halo on highlightand also shows a little strong 2 lines bokeh at peripheral area. I wonder if this lens has a little excessive correction of spherical aberration.
Other petzval lenses I have shows rather soft in general, so I can enjoy a new variations of Petzval.