I've been out of film photography for about a year now and how quickly we forget! I want to shoot some flash photos with my Rollieflex (see model below). Using a basic vivitar connected to the camera, what f-stop and shutter speed do you recommend for flash shots using 100 film? I think I was using f stop 4 or 8 depending on the distance and a speed of 1/60 and got excellent results. But I can't quite remember.