Optical Slave Unit

Optical Slave Triggers – a piece of accessory which is tremendously useful if you work with strobes/speedlights. These are tiny in size but can help you accomplish wonderful photographs. It simply is a light sensitive sensor within which senses the light and triggers the circuit which then ultimately triggers the attached strobe or speedlight.

An old Vivitar 285HV firing off a Optical Slave Trigger

An old Vivitar 285HV firing off a Optical Slave Trigger

Its an economical way to trigger speedlights wirelessly. All you require is to have one strobe(or speedlight) synced with the camera. Now attach the optical slaves to each of your strobe. Henceforth, when you release the shutter, the main strobe/speedlight(synced with the camera) will fire and so will the ones attached to the optical slave units.

However, you need to be aware that these slave units do not work when the ambient light is too strong i.e. during broad daylight. It may even misfire when you have a very bright source of artificial light in its path. So don’t throw away the slave units if you happen to know that they aren’t able to trigger the strobes under broad daylight. Further since these triggers fire when they sense another strobe, they also fire prematurely on the ETTL preflash. Which means, one would need to be aware that these optical slave triggers won’t work well under an TTL environment. Its recommended to turn off the TTL & use the strobes in manual modes in such an environment.

There you go. Purchase some cheap manual speedlights and pair them up with these cheap optical slave triggers to produce some marvelous photographs on a budget.