|Adjustable Landscape Lens No. 1 ML Puligny. A. Darlot (A. Turillon) Paris No. 7574 circa 1897|
This lens is a variable focal length (~ 180 to 360 mm) by changing the distance between the two lens groups with a rack & pinion. Another feature: this lens has two twelve-bladed diaphragms, outside of the two groups, one front and one behind the lens groups. These diaphragms are graduated from 5 to 20 millimeters. Puyo and Puligny published "Les Objectifs d'Artiste" Paris 1906, which outlined their designs for Pictorial lenses. The designs were made by several optical houses of the day. Puligny was the engineer. Charles Emile Joachim Constant Puyo (1857 – 1933), was a prominent french pictorialist photographer.
|Charles Emile Joachim Constant Puyo - Apparition, 1910|
I would add that this lens is extremely difficult to use. Besides requiring constant re-focusing for any focal length change, it is not corrected for chromatic aberration, which means that the apparent focal point is not necessarily what you see in the viewfinder or with live view. Two diaphragms, both of which affect softness and focus, add to the confusion.
Someday I'll figure it out. :) Maybe. In the meantime, I can look at Puyo's image above, and only dream...