In the 1950's you could send your Argus C4 in to Geiss America and they would modify it with their special mount to convert it into an interchangeable lens system.
I acquired this example recently.
After cleaning and bench testing I loaded it with a roll of Fuji 200 and took it, along with the Cintar 50mm lens it came with and a Geiss Lithagon wide angle lens, to the Museum of Transportation.
Both lenses were used. The 50mm lens did great as expected. But I thought the 35mm Lithagon was somewhat soft in the edges of the images, images 5 through 9.

Please click on thumbnails to see enlarged.
All images are Copyright 2015 E.J.Kowalski.
Thanks! Ed