Here is some info:
Page 34 has info on CLE flash.
This is a tricky area as manufacturers usually designed specific products and the electronics so as there is communication between the flash and camera that is needed with TTL. TTL is a system that works with the camera settings and the flash, distance from subject(s) to be photographd, measuring the light needed, then firing the flash. They are usually designed for specific manufacturers cameras. Nikon had their system as well as Canon and others. Some manufacturers designed adaptors where their flashes would work, say a Metz on a Nikon or they built in the units the electronics to talk to each other, in an electrical way.
Other issues. Flash trigger voltage was a problem, particularly with some older flash units.
With my business I used TTL only in certain situations and I froze the camera settings with “manual” letting the computer only control the flash. I found TTL can be easily fooled during some situations.
What did I do? I used off camera flash and ran the flash & camera in manual mode. I controlled exposure on camera with the aperture setting (f stop) as well as the iso. It’s simple with digital slr cameras.
To me, using an on camera flash is like “deer in headlights” or a person attempting to makie a sculpture in just two dimensions. To me, the actual sculpture is what we ‘d be after not the drawing as the final product. Kind of like a rendering but it’s only a step to the final costume.
With photography, we only have two dimensions to work with but we have light and shadows and with those two ingredients we can give the viewer the illusion of three dimensions with our photographs.
Information on TTL flash:
Long winded memo here!
For making photographs, do you think controlled lighting is important?