Hey, I was about to go out tonight to do some portraits of my girlfriend for fun, and was going to bring along my flash for a fill flash. I have an old Yashica SLR and I got to thinking: how the hell do I set the flash and camera so I don't ruin the photo, seen as I don't want to waste film. Here is a picture of my flash unit. The slider selects the ISO you're using, and there is a little red triangle which provides you with an f-stop number. The numbers below that are for the extension of the flash head for wide, "normal" and telephoto distances. If someone could give me some sort of idea as to how to go about this, it would be appreciated.