Can any one direct me to any technical documents available on the web as to how the F 80 meters for the strobes. ( ys-90 underwater photography)
Carl,
The only control your camera has over your YS90 strobes is
1. It will trigger it in manual mode, the output governed by the settings onboard strobe.
2. TTL Mode in A S & P via TTL light sensor that looks at the film.
The camera cannot meter for strobe control as the sensor circuitry is separate. ie. a TTL sensor reads the light of the film plane: Assuming it has had enough it extinguishes the strobe. Accurate to maybe 3 stops.
F80 in program mode, using a YS 90 or two, cannot meter the strobe as part of the more accurate exposure system control measuring ambient light. This is called "Program Flash" and can only be utilised in conjunction with dedicated strobes. In most instances of matrix metering with flash the flash will fire a quick burst nanoseconds before the main dump. The camera adjusts the exposure to suit the information received from that initial burst.
If you require this kind of accuracy you need to buy and house an SB28.