Using EF-500 ST off camera.

Is there a cheap way to use my EF-500 Sigma flash off camera for say a hair light in conjunction with my AB400s?

If it's the EF-500 DG Super, use the optical slave mode. Hit the MODE button until the display says "CO SL". Then hit the SEL button and + or - to adjust the power.

If it's the EF-500 DG ST, you're sunk. They won't even work with a hotshoe adapter.

The st is the basic one and doesnt include an optical slave. It may work with an optical slave shoe?

Curtis N wrote in post #2751292
If it's the EF-500 DG ST, you're sunk. They won't even work with a hotshoe adapter.

Wow! This is good to know.
<commit to memory> get EF-500 DG Super</commit to memory>

Headcase650 wrote in post #2751369
The st is the basic one and doesnt include an optical slave. It may work with an optical slave shoe?

Sorry, no.

The Sigma flashes have a few quirks. To get the Super model to work with a generic (non-E-TTL) hotshoe, such as a hotshoe adapter connected to a PC cord or radio receiver, you need to put it in optical slave mode. I have no idea why.

Unfortunately, the ST model has no optical slave mode, and won't fire with a generic hotshoe. So that rules out hotshoe type slave adapters, radio receivers and the like. They work on the camera's hotshoe or with an Off Camera Shoe Cord 2, but that's it.

I don't own an ST model but this problem has been reported by those who do.