I recently got an old Canon AE-1 film camera back in working order. I'd like to use my modern 430EXII Speedlight flash with it, however since there is no TTL metering, I have no idea how much the flash will affect the exposure of my shot (note that I have confirmed that the AE-1 will trigger the flash). I'd rather not discover that my shots were either blown out or way to dark after going through several rolls of film.
Are there any basic rules-of-thumb or basic calculations for anticipating how much a burst from the 430EXII will affect the exposure of a subject at various distances? Thanks in advance!