2 Flash Question

[Tim Spencer]

I'm moving into 1 off-camera flash in addition to one on-camera flash (real-estate interior photography), I have a question regarding exposure - Canon camera and flashes.

Will the TTL exposure still work? I.e., how does the master know there is a slave and adjust one or both accordingly? That is, how does the set-up "know" to not overexpose?

Does that make sense?

Thanks,

Tim

[bhursey]

How are you triggering the off camera flash?

[Tim Spencer]

>> How are you triggering the off camera flash?

Just a sync cord.

[zona5101]

Originally Posted by Tim Spencer

Just a sync cord.

You will have to manually calculate your exposure and flash power settings. If you were using the Canon flashes in commander mode you could let the camera control the light output...but that will not be the case using a sync cord.

[inkista]

+1 ^^

Unless you're using a hotshoe-to-hotshoe sync cord, you're stuck in Manual on the flashes, without eTTL capability. What I'm confused about is why, if you have two Canon flashes, you're not going master/slave to get eTTL. Do you not have a master-capable speedlite unit? (I.e., two 430EXs?)

With eTTL, the way it works is that the camera tells the flash(es) to send out a "pre-flash" burst of a known brightness level, and then meters the scene. That metering then gives the camera a way of figuring out how much more flash power should be pumped out to get the scene to meter the way it thinks is going to be "right" (you may disagree, which is why FEC and Manual modes are there on flashes). The camera then sets the flash power levels, and you take the picture with the real flash burst.

So, yes, eTTL can compensate with both flashes, since both of them will send out preflashes to be metered and worked into the camera's flash output calculations.

[justin_ing]

If they are both EX model flashes, you should be able to do it if one of them is a 580 (ex or exII)

If not, as everyone has said, its all manual... and easiest way is to move the flashes back from what ever you're shooting.

For real-estate, I would just start at your lowest power on both, and use them for fill.

[Tim Spencer]

Both are 430's so no master - that's why I need a sync cord (or a new flash!)

Thanks all!

[kevingeary]

Originally Posted by Tim Spencer

Both are 430's so no master - that's why I need a sync cord (or a new flash!)

Thanks all!

Unless you have a 7D, you can trigger them using the camera itself?

[inkista]

Originally Posted by Tim Spencer

Both are 430's so no master - that's why I need a sync cord (or a new flash!)

Not necessarily. As the previous poster noted, if you have a 600D, 60D, or 7D, you can also use the pop-up flash in the camera as a wireless master.

If you don't have a master pop-up on your camera, you could also go with cheap radio triggers and using the flash in Manual, not eTTL. Three Cactus V5 transceivers would set you back about $100, but you could then place both flashes off-camera, and you wouldn't have to worry about cables or line-of-sight. You could also get a 1Tx/2Rx RF-602 set on eBay for about $50.

If you wanted to retain eTTL, so you wouldn't have to run around manually to the lights and set the power level on them, but you didn't want another speedlight you could also consider gettiing an ST-E2 (~$220), or the Yongnuo Chinese knock-off of it (~$110).

One of the problem with sync cables, particularly non-TTL ones, is that neither of your flashes has a sync port of any kind. And if you have a dRebel model (xxxD or xxxxD), your camera doesn't have one either. Which means a lot of hotshoe-to-sync adapters. However. If you get three adapters that do hotshoe-to-1/8" minijack, you could use simple mono audio cables from radio shack (and a splitter) to do your syncing.

TTL-capable cables that go hotshoe-to-hotshoe are liable to be as expensive as the cheap radio trigger solution, and splitting isn't going to be as easy as with audio cables.

[Tim Spencer]

Inkista:

Yes, I have a dRebel, so it would require sync adapters. And thanks for the tip about the Cactus V5's! I may give them a try - I had not heard of those and they are way cheaper than Pocket Wizards - thanks!