Other Flash Systems

Studio Flashes

Some Minolta and Sony camera bodies feature a PC-sync socket. It is used to trigger larger studio flashes. These flashes are typically very powerful, are powered via power lines instead of batteries, have a modeling light, and their output can be adjusted. They are, however, not TTL capable. This means that the camera can only trigger these flashes but can not stop flash output. You have to use these flashes in manual mode. You have to use a lot of calculations or an external flash exposure meter to calibrate the flashes.

The Minolta PCT-100 and Sony FA-ST1AM provide a studio flash socket for cameras that do no have one built-in.

This is a more powerful but less comfortable system. But when you use these flashes you (hopefully) know what you're doing.

Slave Flashes

These are either small battery-powered flashes or large studio flashes which are triggered by a pulse of light. The idea is that when the main flash on the camera fires it also triggers the slave flashes. Again, this is a non-TTL system. These flashes can only be triggered, but not stopped by the camera. You have to adjust the output from these flashes manually.

You have to be careful to not use wireless flash or pre-flash metering with the main flash. Otherwise the control pulses or metering flashes trigger the slave flashes, but the shutter is not yet open at this time. You're in trouble when you use a digital camera, because these always either use pre-flash metering or ADI with pre-flash metering for automated flash. You have to switch the flash to manual mode to avoid the pre-flash. Again, if you use such a system you have to know what you're doing.