At the February 2003 meeting, I spoke on the Goerz Hypergon lens. Unfortunately, the actual lens was unavailable at the time. The following month, John Linsky arranged to get the lens and brought it to show the members. John discussed its features as detailed in the Goertz catalogue (Lot 248 in the Shean Auction). See the catalogue section of the auction catalogue. After the meeting I arranged to take a few closeup shots of the famous lens using room light and the assistance of two members to help with make-shift reflectors. The following photos are from that session.
The Hypergon lens is one of a small number of extreme wide-angle lenses based on nearly symetrical sharply curved meniscus elements positioned around a central stop. Click the image to the left to see the actual diagram from US Patent 706,560. This design reduced distortions while providing a flat field across a very wide angle of coverage. Harrison's Globe lens of 1860 was a well known early wide-angle lens based on this concept.
The actual lens is about the size and appearance of a clear glass marble in the centre of a large lens-hood. The maximum diaphram is quite small to help reduce distortion. Since the focal length is very short compared to the coverage, the lens has a deep depth of field. The sample in the auction is a 9 cm focal length "hypergon Dopple-Anastigmat" with two stops.
This image shows the widest aperture marked "48" in the Stolze system (about f/22 in the modern aperture series). This aperture is for focussing and covers a smaller plate. Switching to the aperture marked "96" (about f/31), increases coverage to a plate one size larger (10 x 12 inches). The Hypergon has the widest angle of coverage of any extreme wide angle lens.
In this image of the lens from the rear, you can see the extreme curvature of the glass. The mount is painted a smooth black enamel. the pairs of holes in the rings around the lens glass are used to screw the rings in place. The lenses were made in six focal lengths. All six versions had what was the unique feature of the lens - a star shaped second aperture that could be flipped in front of the lens. Three of the middle focal lengths could also be purchased without this additional aperture. They had less coverage.
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The star aperture was made to spin during the exposure. It acted like a graduated neutral density filter to compensate for the extreme light fall-off at the edge of the plate. The mechanism completely blocks the centre portion of the image. In use, it is flipped out of the way after 80% of the exposure to allow the central area of the scene to be recorded. These images show the lens with the star flipped down (left) and in place (right).
The little nozzle pipe on the left directs air on to the paddles at the end of each arm on the star making it spin. A rubber squeeze bulb (not shown) provides the air. In this example of the lens, there is a broken strut from the axel to the lower rim of the support ring. You can see this better in the following two images too.
This is the back of the star aperture with the assembly flipped down. The green dot is a small felt button that the star rests on (the lens is mounted on a display board).
This image shows the star aperture wheel positioned over the lens. You can see that it completely blocks the central portion of the lens when in position. Each of the eight arms has an odd petal shape with small paddle at the end to catch the air blast.
Here you can see the relative size of the lens and star aperture compared to my thumb as I hold the arm of the star aperture up.
Well that's it for this subject. If you want more information or to bid on this lens go to our Shean Auction page on Antique Lenses & Shutters and look at Lot 09. The images on this page were taken with Nikon 990 digital camera and adjusted in Photoshop. Please note that all images are ©2003 by the Photographic Historical Society of Canada and may be used if the source is mentioned.
Bob Carter
