Rebel t6 slave flash

Hi,

I was hoping to utilise an old manual flash for occasional indoor shots, I have an optical slave flash shoe. The pop up flash triggers the off-camera flash but somehow the shots come out darker than with the pop up flash alone.

Test shots are with everything set to manual, shutter speed tried between 1/60 & 1/200.

Is the camera compensating for the extra light? If so how when everything is on manual?

I appreciate the best answer is to spend a few hundred $$ on a dedicated flash but can't justify it at the moment.

Any assistance greatly appreciated.

Mozz wrote:

Hi,

I was hoping to utilise an old manual flash for occasional indoor shots, I have an optical slave flash shoe. The pop up flash triggers the off-camera flash but somehow the shots come out darker than with the pop up flash alone.

Test shots are with everything set to manual, shutter speed tried between 1/60 & 1/200.

Is the camera compensating for the extra light? If so how when everything is on manual?

I appreciate the best answer is to spend a few hundred $$ on a dedicated flash but can't justify it at the moment.

Any assistance greatly appreciated.

The built-in flash operates in ETTL auto only. It fires a low power pre-flash for metering just before the shutter opens, determines the flash output level needed then fires again when the shutter opens. Other digital SLR camera brands operate similarly.

The 2 flashes happen so quickly you normally perceive just one flash, but your optical slave is reacting to the pre-flash and triggering the slave before the shutter opens. The slave's light fools ETTL metering that the scene is bright so it fires the built-in at a much lower output, and the slave's flash has quit when the shutter does open.

You need "digital" optical slave trigger that ignores the metering pre-flash, or an inexpensive 3rd party radio transmitter/receiver set.