Evan Walsh Posted February 13, 2023 Share Posted February 13, 2023 (edited) Hoping one of the camera technicians on the forum can chime in on this because my googling hasn't brought me any answers. I'm familiar with checking and adjusting flange depth on film cameras with spinning mirrors via a depth gauge kit. I'm trying to understand what the procedure would be for checking flange depth in a camera system that uses a pellicle / beam splitter for their reflex design, like a Bolex or certain Mitchell reflex cameras. Situations where a depth gauge would not be able to go directly from mount to film plane. Thanks! Edited February 13, 2023 by Evan Walsh grammar Link to comment Share on other sites More sharing options...
Premium Member Dom Jaeger Posted February 13, 2023 Premium Member Share Posted February 13, 2023 It’s similar to modern digital cameras where you also can’t use a mechanical depth gauge - you have to optically measure it using a test lens that is perfectly calibrated. With a reflex Bolex you can actually measure the distance from mount to gate with the front removed using a micrometer, measuring from the outside rather than using a depth gauge, but because there are variations in the thickness of the prism (a tolerance value the Bolex repair manuals describe), you actually need to use a calibrated test lens and a collimator to check and set the appropriate physical flange depth. Link to comment Share on other sites More sharing options...
Evan Walsh Posted February 13, 2023 Author Share Posted February 13, 2023 Ah I figured that was likely the case, thanks Dom! Link to comment Share on other sites More sharing options...
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