H16 Prime Lenses
All the Prime lenses manufactured by Bolex are designed for cameras having a C type lens mount and mostly all were produced in two different versions.
The first version was designed for any camera that would accept a C type lens. Which of course included all Bolex H16 cameras.
The markings on the barrel of the lens were designed so that 100% of the light entering was recorded on the film.
The second version was lenses made purely for Bolex cameras where the markings on the barrel of the lens have been changed to take into account the effect of the Bolex prism diverting 25% of the light towards the viewfinder, leaving only 75% to be recorded on the film.
This difference can be seen on all the lenses by looking for the marking "H16 RX" in red on the barrel of the lens.
If present it indicates that the lens is meant to be used purely with a Bolex H16 Reflex camera. If not then you can assume the lens was made for a Non Reflex Bolex camera but can also be used successfully with any other camera which accepts C mount lenses.
Obviously if you use a Bolex H16 Reflex lens on a Non Reflex Bolex or any other camera the markings on the barrel of the lens will be 25% out and therefore under expose the film by 25%. On the other hand if you use a Non Reflex lens on a Bolex Reflex camera you will over expose the film by 25%.
Some of the earliest Kern C mount Prime lenses that were manufactured for use with a Non Reflex Bolex camera or any other manufacturers cameras have a deeper screw thread that if screwed into a Bolex Reflex camera will cause irreparable damage to the Reflex Prism. Take care!