What is an "anachromatic Lens"?

[Hugo Zhang]

I come across the words "Objectif Anachromatique" on an old Frence-made brass lens. Anybody can shed some light on it? This lens appears to be at least 100 year old. It looks like a portrait lens. Thanks.

[Donald Qualls]

It's probably a Frenchified version of "achromatic" -- which, in a 19th century lens, might be exactly that, just an achromat doublet (though most of those had the achromat shaped and mounted as a meniscus behind the aperture and look, from the front, as if there's no glass). You should be able to verify the element/group count by counting reflections, if you have the knack of that.

It might also be a portmanteau of "anastigmat" and "achromat" which would refer to a Periskop, Rapid Rectilinear type, or other early symmetrical design with achromat groups; lenses like that have been made since the 1850s or 1860s.

[Greg Lockrey]

The problem of chromatic aberration has been compensated for using achromatic lenses and apochromatic lenses.

Anachromatic lenses are made of two different materials, which help to negate the dispersal effects of each medium.
Apochromatic lenses are made of three different materials, which virtually
makes chromatic aberration unnoticeable.

[Sven Schroder]

Hi

I think this a pictorialist lens, uncorrected on purpose and I also think it has something to do with pulligny and Puyo (french pictorialists). The seller mentions "1.50, 2, 2.50, 3, 4, infinity symbol" marked on the barrel this for chemical focus correction needed with the materials of the time. A little bit sketchy, but thats all for now and with going to the book shelf etc.
Thanks and Regards
Sven

[Jan_6568]

If this was Puyo-de Puligny Trousse Anachromatique lens then it was indeed a portrait lens. There were versions for 9x12 up to 30x40 cm format made. It was the two element design. I do own their landscape design called The Adjustable Landscape Lens. Mine was made by Darlot. If you want more information search the forum with teh word "puyo". We da the thread about those lenses some year ago or so and a gentelmen from Argentina posted few very nice sample images from the portrait lens and also pictures of the lens itself.
There was also a version which contained housing and cells for both Puyo-de Pulligny designs. You just changed the cells to get portrait or landscape lens.
Colonel Constant Puyo was quite well known pictorialist photographer at that time. Leclerc de Pulligny was more opticien but ha was also amateur photographer. They wrote the book Les Objectifes d'Artiste describing their designs and theory and practice of using achromatic lenses.
I also have a short article on my website on building a replica lens.


regrds,

Jan

[Jim Galli]

I agree that this is very likely a non achromatised lens for the purpose of soft portraits. The earliest pinkham lenses and others also used this device to achieve a pleasingly soft image for portraits. The problem with them is that what you see is NOT what you get. It takes quite a lot of use to be able to predict your results. This fact may have had a part in the naming of the later Pinkham "Visual Quality" series IV where what you saw was exactly what you got.

Make some pictures with it and show us.

[Dan Fromm]

I'm with Sven and Jim. IIRC, Boyer's Opale was an anachromatic triplet intended for use as a portrait lens. Derived, I believe, from the Topaz which was an achromat triplet. Both were anastigmats.

Anachromatic lenses make sense, I think, only for black/white. But since one of my friends has, I think, three Opales I'll ask him how they perform with color film.

[Ernest Purdum]

The prefix "an" means not. It creates a double negative. An achromat is a lens with minimal chromatic aberration. An "anachromatic" lens would be one that does not have that quality.

Not not chromatic is a rather silly name, but we are used to that construction as in anastigmat = not not stigmatic.

[Rider]

This website explains it, in French: http://dioptrique.info/complements/periskop.htm

Note also that the modern 135mm f2.8 Canon Soft Focus lens (for 35mm) is referred to as anachromatique in the French brochures.