Toronto. I chose this lens over a Zeiss Biotar for the standard lens of my late 1950s Exakta-VX IIa. The lens was a fast f/1.9, 55mm lens with full stop click-stops and an automatic stop down to the chosen f/stop and back to f/1.9 after each exposure, ready to view the scene again.
The Zeiss Biotar was a 1928 f/2, 58mm design soon to be replaced by the Zeiss Pancolar lens that was said to be optically better, flatter physically, and had an auto stop down and restoration to f/2 tower much like the one Steinheil used.
I didn’t realize at the time that even “standard” lenses on an SLR may be a slightly longer focal length or slightly retrofocus in design to clear the camera’s mirror. The site shown here covers film plane to lens mount distances for many camera mounts.
The 58mm Biotar and the 55mm Auto-Qninon may be able to focus to infinity using the original none-SLR designs. The lens mount to film plane distance has to be adjusted for the added distance from the mount to the diaphragm which is usually placed at the nodal point of the lens. The rear most element may be inside to camera body (like the Auto-Quinon) but must make room to clear the mirror in the SLR at the infinity setting.
The Auto-Quinon started out as a double Gauss design like the Biotar but had its three front elements increased in size. Looking at the lens, the rear element is about right (around an inch diameter) while the front element is visibly a larger diameter. The lens diagram shows a six element design about a central (unmarked) diaphragm. This is the design, chart, and advertising for the year earlier (1957) version of my lens. The price as shown in US dollars as $169 in 1957 and $140 a year later.
Like all lenses of the 1950s, the lens elements were coated with a thin purplish layer that passes more light. A marketing initiative of the time was to boast a lens was great for colour and had special markings to simplify flash calculations. Have a look here to read about the optical house of Steinheil in a post I made in May of last year.