C-mount Wollensak Raptar 6 inch f/4.5 cine telephoto lens

screwunscrew · Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland

Pictures to come. I only want to share the fact that these are a four-elements design, basically an asymmetric Aplanat like the Busch Bis-Telar of 1905. In other words, a cemented doublet or achromat in front and another cemented rear doublet. The fourth element is quite thick.

Have just disassembled one such lens that showed ugly stains on the back of the front lens or group, something you can’t tell from trying to peep inside. Said to myself I will toss the thing in a bin if the glass has suffered. After cleaning I’m having glass like new. Blooming is intact, too.

screwunscrew · Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland

Let us see: Here are the two doublets in their actual spacing as within the black part in the centre.
The two groups on the right I am not able to disassemble, the left one is heavily lacquered and the right one has an inner tube crimp-locked. I should have to bend it back inwards which I dislike. So I leave both assemblies, have them cleaned, and can lubricate the moving parts lightly.

The shiny tube on the left is made from brass and chromium plated. On the left most is the sunshade ring.

More parts, seen from the opposite direction.

Still another angle

And now let’s have a look at the diaphragm. It was the reason why I bought the lens. It was in disorder, wouldn’t work at all. Took the chance to repair it and found this special make. The pivots consist simply of the stamped-out material, how bold is that! Believe it or not, the little crowns make a rather snug fit with the driving cage but at the price of some uncertainty. They’re really on the short side of things.

Please feel everybody free to ask questions, I shall answer them as good as I can.

calvin83 · Joined: 12 Apr 2009 Posts: 7554 Location: Hong Kong

Nice work!

Most of these lenses are simple telephoto which is similar to Bis-Telar. As far as I know, the Kodak 6 inch f/4.5 sharing more or less the same design.

screwunscrew · Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland

Addenda

I. The Eymax 6 inch f/4.5 telephoto lenses sold by the Bell & Howell Co., Chicago with Made in U.S.A. on the barrel are nothing else than this Wollensak.

II. An error of mine, it’s the third element that is unusually thick, not the fourth.

screwunscrew · Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland

III. All the taking lenses the Bell & Howell Co. sold under their name with an additional designation were from Wollensak.
Designations were Eymax, Extol, Anate, Telate, Anpax, Acura.

screwunscrew · Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland

IV. Extol are Hugo Meyer.

kds315* · Expire: 2021-03-09

screwunscrew · Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland

As a small update I’d like to state that I have learnt to deal with these diaphragms. For the interested, it takes a thorough cleaning, degreasing, and drying. Then everything checked, adjusted, and dusted over with graphite in a plastic bag, excess graphite shaken and pounded off, carefully. After mounted back in place, usually the first step of assembly, closed iris gets wiped over with a soft little toothbrush on both sides. Well done there’s no danger of graphite falling off onto the inner glass. I have just finished work on a Wollensak Ciné Raptar 25 mm, f/1.5. Unfortunately, something else is damaged with that lens, yet for display it’s nice enough.

You know what? The fast Ciné Velostigmat alias Raptar is a six-glass design. To be frank, it’s nothing else than an early Zeiss Biotar.