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The Kern C-mount and D-mount ciné taking lenses
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PostPosted: Fri Jan 15, 2016 2:21 pm    Post subject: The Kern C-mount and D-mount ciné taking lenses Reply with quote

Kern & Co. of Aarau, Switzerland, produced a range of prime lenses for 16-mm. film movie cameras and a line of lenses for 8-mm. film movie cameras. I have collected some general information about them.

All Kern lenses marked AR have an Anti-Reflection coating. This designation has nothing to do with a reflex viewing system, it only means that the lens is coated for better rendition.

Yvar is the designation for triplets with two exceptions. One is the Yvar 25 mm, f/1.8 for 16-mm. film, the other is the Yvar 13 mm, f/1.8 for 8-mm. film. Both have four elements.

Pizar and Genevar for 16-mm. film have five elements in four groups, a design similar to the 1924 Ernostar. Research on the Pizar wide-angle designs continues.

Switar basically are six-element lenses, the 25 mm being a Double-Gauss variant. Why there are 25-mm Switar f/1.4 and f/1.5 I haven’t been able to find an explanation for. Possibly the f/1.5 version was cheaper and pushed into special segments of the market. Pizar 25 mm, f/1.5 are identical with Switar 25 mm, f/1.4 but were sold only as RX lenses.

All Kern lenses marked RX have a positive element in addition to correct for the prismatic displacement of the image plane introduced by the viewfinder double-prism system of Paillard-Bolex H REFLEX cameras. Stopped down to f/3.3 and more or with a focal length longer than 50 mm the error becomes negligible and any lens may be used with Paillard-Bolex H REFLEX cameras. Vice versa a RX lens can be used on any other camera when enough stopped down or of 50 mm focal length or more. Angénieux, Benoist-Berthiot, and Schneider made RX lenses, too.

The C-mount Macro-Switar for the H-8 REFLEX camera are apochromatically corrected. The 12.5 mm, f/1.3 follows the seven-elements Macro-Switar made for the ALPA SLR photographic camera.

The C-mount Switar 10 mm, f/1.6 and the D-mount Switar 13 mm, f/0.9 have ten elements in five groups.


PostPosted: Sat Apr 09, 2016 7:03 am    Post subject: Reply with quote

A PDF of a brochure showing the design of some Kern ciné lenses

http://www.apecity.com/manuals/pdf/bolex_lenses_tech_bulletin.pdf


PostPosted: Sat Apr 09, 2016 8:15 am    Post subject: Reply with quote

Wonderful contribution, thank you so much!!

I always liked them, have a few myself (c-mount and d-mount).

The elusive Macro-Switar f1.1/26mm is not mentioned, as well as the f0.9/13mm d-mount,
do you know more about it?

I also have and like a lot the Macro-Switar f1.9/75mm, is there more about it?
Fantastic lens it is...shoudl use it much more often!

I also have the 5.5mm ASPHERON wide angle adapter, but never succeded to get
it to work.... Does it only work with the f1.6/10mm Macro-Switar?

The RX vs non-RX lenses is an important issue, often overlooked, as RX lenses are
corrected for that 9.5mm thick beam splitter glass cube inside the camera (which by
the old astronomer's rule shifts the focus by 1/3, so about 3.2mm). Could you please
elaborate more about it in praxi? It is rather sad to have to stop down those
wonderful lenses before they deliver the goods (as I shoot open often)....

I found something about it here:
http://city-net.com/~fodder/bolex/truth.html
http://www.c-mountlens.com/2011/bolex-reflex-rx-lenses-the-difference/
http://www.bolexcollector.com/articles/07_03_21.html
http://cinetinker.blogspot.de/2014/12/rx-vs-non-rx-lenses.html (with test pattern images to compare)


Last edited by kds315* on Sat Apr 09, 2016 9:00 am; edited 9 times in total


PostPosted: Sat Apr 09, 2016 8:19 am    Post subject: Reply with quote

Here is a nice 1981 broschure about the cameras and lenses:
http://www.apecity.com/manuals/pdf/bolex_16mm_catalog_1981.pdf


PostPosted: Sun Apr 10, 2016 10:40 am    Post subject: Reply with quote

The RX macro Switar 26mm f/1.1 is a near apochromatic system, built from 1968 on.
I do not know exactly what the design is but I assume seven elements in five
groups, a retro system derived from the Macro-Switar 50mm f/1.8 for 24 × 36.
It has some lateral and little longitudinal chromatic aberration.

The Switar 13mm f/0.9 consists of ten elements in five groups, basically five
achromats with the iris between the last and the second last group.



The (macro) Switar 75mm f/1.9 has six free standing elements.


We could discuss for hours about the Paillard-Bolex cameras and their use but
this is a lenses forum so I think we should abstain. I have repaired RX cameras
and find the mechanics rather delicate, even more so when seen against the
matte surface etched directly on one of the coupled prisms. Optical ruggedness
here and tiny set screws lacquered in very short threads there. Also the long prism
that diverts laterally is set with cork pieces only. They dry out, the prism can come
loose. I have tried rubber pieces and brass bands bent into a wavy form. Everything
is better than Paillard’s super cheap solution.


PostPosted: Sun Apr 10, 2016 3:08 pm    Post subject: Reply with quote

Thanks a lot, ver helpful!! Like 1 small Like 1 small Like 1 small


PostPosted: Mon May 02, 2016 8:21 am    Post subject: Reply with quote

Now it is getting weird. A rather unknown early ciné C-mount Kern lens
is the 25 mm f/2,5. I have deliberately omitted the Yvar brand
because that same design existed already before the 1942 contract
between Kern and Paillard. Have a look yourselves:





These are screen shots out of a video I have found (https://vimeo.com/83959697).

What makes me wonder is the resemblance of the one in the first picture with the Wollensak Ciné Raptar 17mm f/2,7



and of the one in the second picture with the Wollensak Ciné Raptar f/1,9 that was produced both C-mount and D-mount. Only the one in the third image has the outer appearance it then continued to have when given the YVAR designation.

What do you scientists think of this?


PostPosted: Mon May 02, 2016 9:06 am    Post subject: Reply with quote

Many pre-war lenses looks more or less the same to me. Wink


PostPosted: Mon Jun 19, 2017 4:59 pm    Post subject: Re: The Kern C-mount and D-mount ciné taking lenses Reply with quote

screwunscrew wrote:
Yvar is the designation for triplets with two exceptions.


Wrong. The third exception is the Macro-Yvar 150, f/3.3, which has four separate elements, namely an additional one in front of the frontal positive element. Logical, for shorter conjugates. I know because I have disassembled one today, pictures to follow.

It seems appropriate to assume that the 100 mm Macro-Yvar is a four-elements lens, too. That needs confirmation.


PostPosted: Tue Aug 22, 2017 3:56 pm    Post subject: SPECS Reply with quote

If the picture upload worked the enclosed graphs of the Cine Switar correction state might be of interest

p.




PostPosted: Tue Aug 22, 2017 5:53 pm    Post subject: Reply with quote

Looks indeed excellent, thanks for sharing Paul!