I have made some better camera mounts and fixed the Fujian 50mm lens core furthur from the film plane with stacked CS-Mount - C-mount adaptors to compensate optically for the polygon prism. Until I have an alternative lighting system of lower power, artifacts from stopping the lens down and blemishes on the ND filters in the lighting path remain visible.
I have determined that it should be possible to conveniently mount an interruptor disk on the prism drive which although it rotates at a different speed, registers back to a zero point on the film drive sprocket every three rotations of the prism drive. There is a bonus in that the prism drive is damped against backlash by a spring-loaded felt brake pad.
The hall-effect or optical interrupt sensor should conveniently mount to the plastic gear cover and thus avoid having to build new support structure. This arrangement will require an added hub extension through an existing adjustment hole in the plastic cover and a longer through-bolt to secure the prism holder. If the prism is eliminated, then a dummy prism holder would need to be substituted.
For now, with the SI2K, the polygon prism remains necessary because the camera is a rolling shutter type and requires an intermittent film movement to avoid artifacts.
Here is a link to another test with the camera in a better fixture. Old B/W film reproduces better than colour at this point in the progress. Cyclic prism artifacts are apparent because the camera is running wild and not slaved to the Steenbeck’s frame rate. Optical resolution is adequate as dust on the film shows sharply. The fixed soft spots are on the stack of ND lighting gel pieces which remain in near-focus due to the deep depth-of-field of the lens at f16. I am thus encouraged to continue.
