Puyo lens

[community1313]

Today I learned a bit more about "chemical focus" and I am going to try to make it more understandable here.
Chemical focus is just a name even if it sounds your film or plate are going to catch fire or something, it's a convention to select focus on the blue image, makes sense if you need contrast. See the puyo lens is made to keep some chromatic aberration, there are two types of aberration, lateral and longitudinal, since the lens is corrected for spherical aberration it makes sense to consider the maker just kept the longitudinal, the image will be separated in different colors with different planes of focus, one after the other, "a la queue leu leu" (excuse my french), so if you focus on blues the reds will be blurry, it's a question of choice! If like me you experienced infra red photography you must be used to defocus a bit when you shoot infared film, some SLR lens even have a scale for this but on apochromatic lens there is no need for such a chemical focus.
Apparently Darlot/Puyo had a demi anachromat (like the P//S).
I can't wait to shoot color, it should produce color halos but no rainbow fringes (that would be a lateral chromatic aberration)
I hope this was helpful and anyone correct me if I am wrong!

[community1313]

Found this excellent article..
http://etudesphotographiques.revues.org/index2676.html

[Steven Tribe]

Interesting images and nice to see Puyo as an artist rather than a name on a brass barrel. Portraits appear to age better than landscapes!

[eddie]

so can i extrapolate that if i focus on the blues ten the blue will be in focus? will this work for any color or just blue?

i will try and translate the above article.

keep us posted.

eddie

[cowanw]

so can i extrapolate that if i focus on the blues ten the blue will be in focus? will this work for any color or just blue?

i will try and translate the above article.

keep us posted.

eddie

Yes it works for any colour. In bygone days the plates were only sensitive to blue light but the focusing was done by white light as this is what our eyes are sensitive to. So adjustment for focus was required. Todays wet plate will be like this
As todays film is sensitive to all colours of light, the lens will show the effects of both focus and non focus.
You may pick a colour by filtering, say with a yellow filter, in which case wysiwyg. and no focus alteration is required because you are now not focusing by white light. Or you may choose a blue filter to simulate the nature of blue sensitive film.

Regards
Bill

[community1313]

So mystery gets deeper, the lens functions like the landscape one, what looks like a focusing knob is actually changing the distance between the two simple elements
The range is 45 mm and there is a scale on the lens. Aperture goes from 9 to 50 (is this actual "modern" apertures?) Serial number is 36147. Barrel is aluminium and constuction quality excellent (I am always dazed about how well made those lens are, hand made!), it's indeed written "tele anachromate d'atelier" "constant puyo"
Glass is signed darlot but no date, just the serial number.
I always get the odd one, all the better, but if anyone has more info about it?
I would presume this is a later construction and a mix of the landscape lens and objectif d'artiste..Next step is cleaning, the glass is very good but I am going to shine this barrel a bit and then post some photos of it!
Happy haloween!

[community1313]

next time i am in paris lets go shoot. i had some great times last june when i was there.

okay. can some one post what the lens formula is? a picture of it? i think i got one! a big F#$%er for sure! lets talk. and then we can all try and figure out how to shoot with it.

based on the description i think this is the same formula. it is french for sure ( i bought it in belgium from a guy who got it in paris.....), but no maker's name.

eddie

ps. $610 is a steal. well done!

Looks like a big petzval..have you opened it to get a close look, pritty anyway!

[community1313]

Today I ran a test on the lens, focal goes from 12 to 19 inches/ F6 to F9 maximum aperture, since I used it on my arca I had the bellow very streched, not a 4x5 lens.
As it goes in color what you see is what you get and it works nice closed one stop and gets sharper after (much like a verito) but never gets very sharp. Colors are fused and glowing and it's very elegant and to my surprise nice contrast. Focusing is not crucial since plane of focus is quite wide and you do notice the shift of colors. I will scan the polaroids and post them soon.

[evgenys]

I have the similar lens but my lens has the word "Trousse" instead of "Tele", made by Darlot, No.36667.
But! The lens has the different design. The lenses are the same: plano-convex on front with the convex side towards the photographed object and the plano-concave on the back, but this lens is reversed comparing to the "Adjustable landscape lens" formula: the concave side looks not towards the film/plate, but to the plano side of the front lens.
The all other things (like markings on the barrel) are the same as on the other Puyo lenses I saw here and in the Internet.
I didn't use the lens yet, because I had to make flange for it, but hope to try it in the nearest future.
Garrett and Jim, thanks for the tips how use them properly!

[Steven Tribe]

This is the remains of the casket set mentioned in VM. A set seen by them had the serial number 35,82x. But they talk about a set of 4 concave/convex lenses.