How do I get my Sony RX10 to effectively trigger an old studio flash?

Question

I'm new to digital photography, got myself a Sony RX10 and I want to get it to trigger my old Portaflash 336 VM heads. They've got built-in opical slaves. I tried setting the camera on manual, reducing the output from its fill-in flash, setting the white balance to 'flash', setting the aperture from a separate meter reading and shooting at a range of shutter speeds. The camera's flash triggers the Portaflash heads but I only get a very dark image lit by the ambient light. What am I doing wrong? Would it work if I had a radio trigger?

John M

Answer 1

Your built-in flash has no manual mode. The TTL pre-flash is causing the optical slaves to fire at the wrong time. The easiest solution is to use a simple manual flash in the hotshoe of the RX10.

Answer 2

The RX10's built-in flash is TTL-only. With TTL, the camera tells the flash to send out a "preflash" burst of light that it can meter, and then the camera automatically adjusts the flash's power output to get what its auto-exposure system thinks is good exposure, before sending out the main flash burst while opening the shutter for the exposure. This pre-flash is setting off your studio flash's optical slaves too early.

The easiest solution would be to use an external flash on the hotshoe of the RX10 that can be put into Manual mode to eliminate any preflashes, but yes, you could also simply use the hotshoe of the RX-10 with radio triggers to set off your Portaflash heads. The 336VM has what looks to be a 1/8" (3.5mm) miniphone sync port. You'd just need the right cables to connect a receiver to each light.

You do have to be careful not to pick a transceiver unit that requires a Canon/Nikon TTL signal to switch between Rx/Tx mode, but a lot of cheap radio triggers are liable to work (e.g., Yongnuo RF-603II, Phottix Strato, RadioPopper JrX, etc. etc.) Radio triggers these days can be relatively cheap and eliminate the line-of-sight requirements of optical slaves, so they're pretty popular.