I've built a water droplet photography rig, and the last piece of the puzzle is finding the right flash setup. I have a Canon 6D, and I already have a Canon 320EX flash. I need at least one more flash so that I can light the setup well, have multiple flash colors, etc. I'm thinking I'll get a 430EX II.
I have thoroughly scoured the internet for answers, but I can't figure out the best way to trigger the flashes. Due to the nature of water droplet photography, neither flash will be on the hot shoe of the camera, they will both be remotely located, although only a few feet away from the camera.
I know that the flashes can be triggered with an IR signal, or a radio signal, or using a sync cable. I know that some of these options allow the camera to tell the flash what its output power should be, and some of these options don't allow that. But it's hard to tell which one is which. I would prefer to have an option that allows for the automatic adjustment of flash power, because the 320EX doesn't have a manual adjustment on it, and I'll need to have the flashes operating around 1/64 power (or less) to keep the flash duration as short as possible, so that the water droplets aren't blurry. Does the 320EX support having its output power automatically adjusted when it's not sitting directly on the hot shoe?
If I use sync cables, will that transfer the information to control the output power of the flashes? Can I "split" a sync cable so that it can connect to both flashes?
If I use IR, what's the best transmitter (since the 6D doesn't have one built in)? Do both the 320EX and 430EX II support this mode of triggering? Will it transfer the information to control the output power of the flashes?
If I use radio, what are some good transmitter/receivers? Will they transfer the information to control the output power of the flashes? (I do some other work that would benefit from the long range of radio triggering, so this might be the best option.)
Any advice would be greatly appreciated, my head is spinning from trying to read through product specs and reviews to discover this information. Thanks!