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screwunscrew
Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland
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Posted: Mon Jul 11, 2016 3:05 pm Post subject: C-mount Wollensak Raptar 6 inch f/4.5 cine telephoto lens |
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screwunscrew wrote:
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. |
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screwunscrew
Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland
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Posted: Sat Jul 30, 2016 4:52 pm Post subject: |
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screwunscrew wrote:
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. |
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calvin83
Joined: 12 Apr 2009 Posts: 7555 Location: Hong Kong
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Posted: Sat Jul 30, 2016 5:06 pm Post subject: |
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calvin83 wrote:
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. _________________ https://lensfever.com/
https://www.instagram.com/_lens_fever/
The best lens is the one you have with you. |
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screwunscrew
Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland
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Posted: Mon Oct 10, 2016 7:06 am Post subject: |
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screwunscrew wrote:
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. |
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screwunscrew
Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland
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Posted: Tue Feb 07, 2017 8:03 am Post subject: |
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screwunscrew wrote:
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. |
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screwunscrew
Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland
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Posted: Wed Jun 21, 2017 8:46 am Post subject: |
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screwunscrew wrote:
IV. Extol are Hugo Meyer. |
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kds315*
Joined: 12 Mar 2008 Posts: 16625 Location: Weinheim, Germany
Expire: 2021-03-09
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Posted: Wed Jun 21, 2017 9:41 am Post subject: |
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kds315* wrote:
_________________ Klaus - Admin
"S'il vient a point, me souviendra" [Thomas Bohier (1460-1523)]
http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
https://www.flickr.com/photos/kds315/albums my albums using various lenses
http://photographyoftheinvisibleworld.blogspot.com/ my UV BLOG
http://www.travelmeetsfood.com/blog Food + Travel BLOG
https://galeriafotografia.com Architecture + Drone photography
Currently most FAV lens(es):
X80QF f3.2/80mm
Hypergon f11/26mm
ELCAN UV f5.6/52mm
Zeiss UV-Planar f4/60mm
Zeiss UV-Planar f2/62mm
Lomo Уфар-12 f2.5/41mm
Lomo Зуфар-2 f4.0/350mm
Lomo ZIKAR-1A f1.2/100mm
Nikon UV Nikkor f4.5/105mm
Zeiss UV-Sonnar f4.3/105mm
CERCO UV-VIS-NIR f1.8/45mm
CERCO UV-VIS-NIR f4.1/94mm
CERCO UV-VIS-NIR f2.8/100mm
Steinheil Quarzobjektiv f1.8/50mm
Pentax Quartz Takumar f3.5/85mm
Carl Zeiss Jena UV-Objektiv f4/60mm
NYE OPTICAL Lyman-Alpha II f1.1/90mm
NYE OPTICAL Lyman-Alpha I f2.8/200mm
COASTAL OPTICS f4/60mm UV-VIS-IR Apo
COASTAL OPTICS f4.5/105mm UV-Micro-Apo
Pentax Ultra-Achromatic Takumar f4.5/85mm
Pentax Ultra-Achromatic Takumar f5.6/300mm
Rodenstock UV-Rodagon f5.6/60mm + 105mm + 150mm
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screwunscrew
Joined: 20 Nov 2011 Posts: 59 Location: Äsch, Switzerland
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Posted: Fri Jun 18, 2021 5:53 pm Post subject: |
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screwunscrew wrote:
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. _________________ https://www.film-mechanik.ch/ |
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