Is there an adapter that will take a Bolex Bayonet mount lens and convert it to mount a C-mount camera? I've seen a lot of adapters that go the other direction.
Bolex Bayonet Mount
Posted 16 October 2016 - 07:45 PM
Posted 16 October 2016 - 08:54 PM
I think there are a number of issues, which might explain why no-one has made such an adapter.
Firstly, as Nicholas mentioned, the difference from bayonet flange to C-mount flange is only about 5.5mm, which doesn't leave too much room for the material thickness of the bayonet flange and the lock ring threads.
Secondly, the large diameter of a Bolex bayonet mount sitting almost flush will hit protruding parts of a C-mount Bolex turret - the centre screw, turret lever, edge lock, and any mount caps for the other 2 mounts, including the bottom locking one which is pretty important to stabilise the turret. You'd probably find a number of other C-mount cameras that have some sort of protrusions within a 40mm radius of the mount.
Thirdly, the reason Bolex went to a bayonet mount for the heavy zooms of the SBM, EBM and EL era was because the weight could flex a turret and alter the crucial flange depth. So even if you custom machined an adapter and removed any protruding obstacles in order to mount a bayonet zoom, it might not be worth it for the possibly soft images or potentially damaged camera mount. Even a non-turret C-mount camera could have the front plate distorted by the weight of a heavy zoom.
But in theory, it's possible, and a lens support could protect the mount.
Posted 16 October 2016 - 11:10 PM
Posted 17 October 2016 - 03:09 AM
Good, I’d have explained the same way but Dom beat me. The Paillard-Bolex H camera was designed in 1930-31, its front and turret plates got redesigned in 1953-54 and again in 1955-56. Heavy lenses are not meant to be used with this “professional amateur” camera as it went in the publicity from 1937 on. The zoom lens challenges the older concept.
A choice of lens ports on a turret has a number of advantages one must learn to appreciate. I do appreciate the following ones:
- Compact and lightweight primes
- C mount allows the use of shim rings (with older lenses that have long mounting threads)
- Use of the rackover system which is more easily controllable by a technician than a reflex system
- “Vertical” shifting of a lens to some extent
- Use of auxiliary equipment attached to the turret via one or two lens ports, for example a bellows holder
The coolest of all turrets was known with the Askania shoulder camera of 1935, it has a spring that can be wound up and then made to revolve step by step, even while the film is running. Clack, clack, clack, clack, two revolutions.
Posted 17 October 2016 - 12:11 PM
If you happen to be talking about the later version Vario-Switar 16-100mm, Parts are available from Bolex to convert the bayonet mount to a C-mount.