Cactus v2s and FEC

[177ichael]

Can you control FEC with the Cactus triggers? With Pocket Wizards?

[hexa]

No and no. They transmit only the firing signal.

[tim]

Yeah, all they say is "fire". FEC is only for use with ETTL, not manual flash.

You can do this i you get radio poppers, which do ETTL via radio. They're expensive though, and new.

[177ichael]

Just got my Cactus V2s and performed the mod to the transmitter. Works well for my purposes so far. I was curious about being able to adjust the FEC from my camera when flash is off-camera, but I guess it's not a huge issue since the flash is being bounced. Even if the flash is set to 1/1, adjusting ISO/aperture, will yield results I'm looking for. Although, I hate to waste battery power at 1/1 when bouncing if not needed, so I'd rather find the right lighting by adjusting flash output.

Still learning, but it seems like FEC is most critical in situations like outdoor fill-flash, when FEC might want to adjusted to balance ambient with fill. Although, it might also be useful indoors if trying to expose for the indoor subject and also expose correctly for windows, etc. For my purposes, bouncing and setting the off-camera flash to manual seems to do the trick. Thanks!

[tim]

FEC only works in ETTL, when you're using radio triggers you're using full manual. If you have the transmitter connected to the PC port and a speedlite on the hotshoe FEC will adjust the output of the speedlite.

[CliveyBoy]

E-TTL is a two-way communication stream (a dialogue) between camera and flash, either hardwired or through a Canon IR setup. The IR can be extended using RadioPopper 916MHz radio in the chain.

Radio triggers use a monosyllabic monologue, "Fire!". There is no other communication from the camera, including FEC. The user must set the power levels, etc, on the flash.

There are special cases such as a radio trigger firing a flash in manual mode and set as a Master, which can cause another flash set as a slave in ETTL mode to fire, and use the Master's settings to do so. It uses only a subset of the ETTL capabilities.