2014Off Topic forum
Panavision camera 200-degree shutter mechanism and exposure compensation
12 years old. Gear and prices may have changed since.
What the thread found
- Early Panavision PSR cameras featured 200-degree shutters as a default configuration rather than the standard 180-degree shutter
- The 200-degree shutter worked in conjunction with a bowtie-style mirror reflex system that increased film exposure compared to standard 180-degree shutters
- A 200-degree shutter provides approximately 11% more exposure than a 180-degree shutter by extending exposure time from 1/48 of a second to 1/43 of a second
- The bowtie mirror reflex system used two 80-degree mirrors instead of a single 180-degree mirror
- Despite the increased shutter angle and exposure time during filming, the film stock still advances at 24 frames per second and projects normally at 24 fps, making the extended exposure invisible to viewers
- Panaflex cameras allowed operators to adjust shutter angle using a manual wheel control
- On Panavision cameras, the mirror and shutter are mechanically linked and operate in synchronized fashion at the same rotational speed
Depends on
- Details about the exact mechanical relationship between the bowtie mirror and pulldown claw timing remain somewhat speculative based on internship experience rather than technical documentation
- The explanation of how frame advancement timing compensates for increased exposure time is presented as logical conjecture rather than confirmed engineering specification
- Unclear whether all early Panavision models featured 200-degree shutters or only specific variants like the PSR