03-03-2016 06:32 PM
Why do you want a "light meter" to set off the flash?
You can get flash triggers that will fire the flash when it sees another flash go off, but you need to make sure that it understands the canon flash and ignores the exposure setting pre-flash.
Other than that, you are much better off using Canon's optical or radio wireless flash capability to trigger external flashes.
03-03-2016 06:56 PM
A light meter that will set off the flashes.
The metering inside of the camera already does that. It even adjusts the intensity of the flash for you.
03-03-2016 08:58 PM
You could use something like this to set camera and flash settings. It won't trigger anything but it will give you the proper exposure setting. Then you trigger flas by operating camera.
03-04-2016 08:16 AM
I think an online retailer, like BHPhotoVideo, can better help guide you. They have online experts who really know their stuff, and actually try to find the "best fit" solution for customers.
03-04-2016 10:25 AM
This is common in studio photography. I have a Sekonic L-758DR that has a built-in radio trigger for PocketWizard receivers. This way you can walk up to your subject, hold the incident meter at the point where you'd like to meter the subject (hopefully not standing in the way of your own flashes) and trigger the studio flashes while metering at the subject (you don't have to walk back to the camera).
Unfortunately I'm not aware of a meter with a built-in radio trigger for the new Canon radio technology flashes. I think you may have to use a Canon RC-6 (ir remote) to trigger the camera while metering -- not as elegant a solution.