Could it be a SF1? That would allow the combination of flash units you mention.
Originally Posted by amundenovskiy
Anyway, to clear up a couple of things for you:
ISO is the FILM speed and tells you what film is more or less sensitive to light.
Shutter speed is 1/2 of the combination for correct exposure. When the shutter speed is set to a high speed, you can freeze motion of a fast moving subject.
When it is set to a slow speed, that same subject will be blurred.
F stop (or aperture) is the second half of the exposure combination, when the combination is correct you have proper exposure. When it's wrong your pictures can be either light or dark. Some people refer to apertures being "open" or "closed", "higher or lower" and the language can be confusing.
Open or lower mean the smaller values on the lens but the bigger opening. Closed or higher are the larger numbers, or the smaller opening.
The more common use is opening up or stopping down the aperture.