C-mount
Originally the C-mount was no affair concerning still cameras. The one inch screw-mount was one for cine lenses, used on 8mm cine cameras, surveillance cameras and TV-cameras. Old sophisticated cine cameras had a revolver with several one inch threads to hold a whole set of C-mount lenses. After the invention of the zoom lens the most cine cameras lost this revolver feature.
Cine cameras need fast lenses because of shooting 18 or more images per second. That's the reason for a completely different culture behind the large variety of cine lenses. Thus f1.2, f1.4, f1.5, f1.8 and so on are typical standard lens speeds of these items, whilst f1.7, f1.8 and f2.8 are the most common standard lens speeds of still cameras.
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| Schneider-Kreuznach 1:1.5 25mm Xenon on Micro 4/3 adapter image by mr. wood |
Since Olympus and Panasonic had introduced the first cameras for the Micro Four Thirds autofocus lenses there are still cameras in the market with a flange focus distance almost like that of the C-mount lenses. That was the first chance for photo amateurs to think about using C-mount cine and CCTV lenses on still cameras. Soon the adapters were available, even cheap ones made in China. When Sony introduced the concurrent Sony NEX camera system the adapter makers offered C-mount adapter for the NEX too.
