T3i with a 580ex

[lennon33x]

So a friend of mine has a T3i and a 580 ex and she is trying to do OFC. She's trying to figure out how to trigger it to fire. I looked in the manual and apparently you have to have the 580ex operate as a "transmitter" to another flash, so that the second flash fires. Is this true? Other than the ST-E3-RT, is there another way? I'm assuming that there has to be a transmitter in the hot shoe, and that the T3i doesn't have a built-in transmitter. Thanks

 

[GlennT]

I don't have a T3i, but look in the menus for "Flash Control." You can find detailed instructions out there, particularly on Youtube. You mostly have to enable "Flash Control" in that menu, set a couple things, then set the flash to slave mode with matching settings. The built in camera flash has to be up, even if you select the mode that only "fires" the Speedlight and not both the Speedlight and built in flash. It will fire a small amount of light from the built-in flash to trigger and control the external flash, but not enough to contribute to the exposure. The Speedlight has to be able to pick up the light from the camera though, so it can be somewhat dependent on line of sight.

If there are two 580EX Speedlights, you should be able to use one on-camera as a master (i.e. transmitter.) with the 2nd in slave mode.

For a manual setup, you can use inexpensive triggers such as those from Yongnuo with are RF based and thus not dependent on line of site to fire reliably. E-TTL enabled triggers are out there, but they're more expensive.

 

[wyogirl]

you can also buy radio triggers... one part sits in your hot shoe and one part attached to the flash.

 

[lennon33x]

I have a Pixel King/Opas system that I use and I love it. She just wants to do something similar, and I'm not as familiar with her camera or her flash. I actually use a Triopo OCF with my RF triggers. I just didn't know if the on camera flash had to be up to trigger it as a slave, or if there was some innate feature in the camera the sent an RF signal.

 

[JacaRanda]

Here you go.

 

[TCampbell]

The T3i was the first model which allowed using the built-in pop-up flash as an optical trigger for off-camera slaves.

Note that when you do this, you will see the flash on the camera fire but it will not *necessarily* be in the photo.

When using E-TTL, the camera meters the shot, fires a "pre-flash" to evaluate the light with flash-power, then decides how much power to use once the shutter is open, opens the shutter and fires again (this time using the calculated power output level.) This all happens so fast you'd generally only think it fired once.

You can put the camera in a mode where the T3i only fires the pre-flash (and instructs the 580EX II to fire... but once the shutter opens, the on-camera pop-up flash actually does *not* fire a 2nd time so that it won't spoil the shot.

The 580EX II must be put in slave mode. To do this, press-and-hold the "Zoom" button (the icon next to the word zoom that looks like a zig-zag arrow is Canon's icon to indicate you want to link it to other lights). You will need to hold it for about 2 full seconds. The lcd will display the flashing word "Off" and the icon of a flash with that zig-zag arrow in front of it. Let go of the zoom/zig-zag button and rotate the dial clockwise two clicks until the LCD reads "SLAVE on". Press the "set" button. The flash is now configured to fire as a slave. Note that you can set the group (I think it defaults to group A which is probably fine with your camera.) The "groups" allow you to configure multiple flashes and have different power levels on different flashes (you can even turn groups on and off) to control the light. Repeat the process but dial it back to "off" to switch the 580EX II out of slave mode and back to normal mode when you're done.