Dr. Rudolph. Hugo Meyer & Co-Goerlitz & New York. Nr293184.Double Plasmat 1:4 Foc.7 3/4 inches.Pat.
Rear lens is marked; Plasmatlens 1:8 Foc.12 5/8 inches. Nr.293184
From ihagee.org; The coverage of this lens "according to Dr. Rudolphs patent" is;
f/4 coverage 6 1/4" x 4 3/4"
f/22 coverage 10 1/4 x 7"
camera-wiki.org serial number list says this lens (sn. 293184) is from 1925-1930.
This is a pre WW2 lens, there is no anti-reflection coating.
This is a special "convertible" lens; the front lens group can be unscrewed and the rear lens used by itself as a 12 5/8 inch (320mm) lens. With the front lens group in place it is a 7 3/4 inch (197mm) lens.
A 1938 British ad shows a similar lens (stating 7" focal length), see photo.
This lens has no focus method or shutter, these must be supplied by the camera.
The supplied mounting plate is 3.275" square. It is beveled on one side.
The rear of the plate has a raised lip of 2.9" square.
Condition:
Front and back of lens are in excellent shape, no visible scratches.
Aperture works smoothly.
Black finish is worn in spots.
Both front and back lens cells have a slight internal haze (maybe due to cementing of the glass elements). It is not on the internal lens surfaces that are open to the air.
The front and rear lens groups have matching serial numbers.
Shipping will be by UPS ground using the automatic discounted Ebay rates.
Customers can return items for any reason, but must pay shipping both ways if there is no problem with the item.
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