zeitz

This is my favorite thread on both the International and German sides of the Forum.

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LTM is NOT M39. LTM is 39mm diameter by 26 threads per inch (tpi). LTM should be referred to as L39. M39 is 39mm diameter with a metric pitch. There are coarse and several fine metric pitches that are part of the metric M39 DIN spec. Leica lenses, ignoring Visoflex lenses, are also 28.8 mm from the rear lens flange to the focal plane, called registration. To be compatible with Leicas, a lens must have 39mm diameter, 26 tpi, 28.8mm registration and compatible RF coupling. The Soviet manufacturers used an RF coupling that sometimes can be incompatible with Leicas. The other manufacturer that was deviated from the definitive L39 thread was Canon. Their original J series lenses were M39 x 1.1mm pitch, then they made a Universal 39mm mount that would work on either camera by using sloppy threads. (Peter Dechert, Canon Rangefinder Cameras 1933 ~ 68, pg 14.) Canon finally settled on true L39 in 1952. The J series may have been different to avoid any legal action from Leitz. After WWII any manufacturer could use Leitz intellectual property with fear of legal action. The only camera I know of that is true M39 is the Braun Paxette, but with a different registration. One of the Compur shutter sizes is M39.

I am envious, Wilfredo. Portugal seems to be a wonderful locale. I am curious as to why you question whether VAT would be charged? I didn't know there were any exceptions.

Back row - Kilfitt, Astro-Berlin, ?, Novoflex, Tewe. How well did I guess?

The enlarger really needs to be rewired. You need a three wire system with the equipment ground connected to the chassis. I have also found the insulation that is used on Leitz equipment to age and crack.

One of the issues I have in general with real auctions is that the provenance of the item is impossible to trace backwards because the owner is anonymous. There have been a number of items on the Leitz Photographica Auction recently that I truly question the authenticity. These items were from Soviet era manufacturers. The prices were so high that it is highly profitable for a skilled artisan to manufacture them. At least on ebay a potential buyer can contact the real seller, often the owner, during the auction.

I have over 950 transactions on ebay over a 23 year span. (Not all transactions were for camera equipment.) I have only had one bad transaction which implies 99.9% honest people. The seller refused to ship a Nikon Model 1 reflex housing even though I had paid for it. Ebay refunded by money. Ironically the same reflex housing showed up at Dan Tamarkin's annual auction a year later. I won it again, and the second time at a lower price. For me Ebay is an essential market from tiny camera screws to extremely rare and unusual camera equipment.

You don't say if you are working with a .dng file or a .jpg file. Also you don't say if you are storing the edits in the .dng file or in an .xmp file. My only guess, and it is a pure guess because I use Photoshop and not Lightroom and I always use .xmp files, is that there is some limit on the number of edits / layers that can be put in a .dng file.

At one time Back's company must also have been called The Viewfinder Corporation. Maybe the sequence was "Research and Development Laboratory" to "The Viewfinder Corporation" to "Zoomar Inc". https://collection.sciencemuseumgroup.org.uk/objects/co8206396/zoomar-variofocal-lens-lens I also clipped the attached text from an article by Back in March 1947 issue of the American Cinematographer magazine. At that time the zoom lens was already labeled Zoomar, but the company name Back used for his byline on the article was Research and Development Laboratory. So we know the principals involved in the development of the OP's viewfinder, but we haven't found anything giving details of the Camera Supply Co. Anbaric's post shows the company existed at least by 1944.

You may also notice that the discussions tend to drift off-topic. One line of thought often triggers another line of thought. It is fine to bring us back to your original interest. I think I may remember Camera Supply Company. I looked through the period camera magazines that I have, but I can't find an advertisement from them. The next time I get to a major library, I will search more broadly in 1950's magazines. Forum rules only prohibit members from giving estimates of equipment value. The Forum is not involved in pricing.

Luigi's quote from the viewfinder patent got me thinking further about events in the US camera industry. We read in Anbaric's posting that Edward Kaprelian was the chief of the US Army Signal Corps lab not far from New York City. Dr Frank G. Back also worked for the US Army Signal Corp during World War II and lived in the New York City area. It is almost certain that Dr Back worked for Kaprelian and that they both shared ideas. Dr Back is credited with the invention of the optically compensated zoom lens, applying for a US Patent in 1946 and awarded Patent Number 2454686 in 1948. The description of the operation of the viewfinder, quoted by Luigi, matches the operation of an optically compensated zoom lens. Previously zoom lenses had complex mechanical linkages to perform the compensation. The original name for Dr Back's company started in 1944 was Research and Development Laboratory; the company's name was changed to Zoomar in 1953. Dr Back's Zoomar company produced the first zoom lens widely used by the TV industry, the first zoom lens for 35mm cameras, the first zoom lens for medium format cameras and the first zoom lens with macro capability. I suspect he designed the Kilfitt Multi-Kilar variable teleconverter, but I cannot find the patent application for this device.

Wow. Who would have thought this little viewfinder would lead into one of the more significant events in the history of photographic equipment? The Barringer & Small book "Zeiss Compendium East and West - 1940-1972" goes into detail in Chapters 1 and 2 on the events leading to the lenses getting into Kaprelian's control. Patton's Third Army took Jena on April 13, 1945 even though Jena was supposed to be left for the Soviets. Jena was handed over to the Soviets in July of 1945. I have seen magazines in the US Library of Congress that are marked as belonging to the Carl Zeiss Jena library. Some of the lenses were sold off to Burke and James in Chicago and resold to the public with the Carl Meyer brand. I'm sure the brand was selected to confuse the public.

It is easy to do a US Patent search. But I can't quite read the Patent Number.

A Kontur finder could be bought as a separate finder. Kontur finders are neat devices. I am surprised others did not use this approach - both eyes were open; one eye saw the frame line and the other eye saw the scene. There was a 150mm lens planned, but it never materialized. The rear element of the lens, being part of the back side of the reflex housing, greatly limited lens design. The interchangeable lens was really only an interchangeable front element. One normally wants reflex focusing / viewing for fast aperture lenses, long focal length lenses or close-up work. The Prominent reflex housing provided none of this.