If you want to get into off-camera flash using your speedlight, one of the first problems to solve is how you’re going to trigger your flash when it’s moved off the camera. For many Nikon photographers, it’s just a simple matter of diving into the in-camera menus to activate the pop-up flash as a commander for the Nikon CLS system. In the Canon world, recent cameras have copied this type of functionality so that the pop-up can trigger flashes using the Canon optical triggering system. Yes, some kind of radio triggering solution is better, but this kind of basic triggering capability with the pop-up flash is a lot better than nothing.
If you shoot with a Canon camera that doesn’t have a pop-up flash (eg. 5D, 6D bodies) and you already have a Canon flash (eg. 580EX, 430EX, 600EX) you’re simply out of luck: you have to go out and buy some kind of component to act as a trigger. You can buy a Canon ST-E2 optical trigger but that product has always been a bit crap and has now been superseded by the ST-E3-RT radio trigger. If you wanted to try the ST-E3-RT you first have to deal with the rather unfriendly $250+ price tag.
You could buy a second flash that can act as a master but that seems excessive (in size and price) and seems like a waste of a perfectly decent flash if it’s only used as a master. You could give up on Canon-branded gear and buy some third party flash trigger but then there’s a whole another drama of figuring out what gear to buy (do you want TTL or not? etc). It leaves you wishing your camera just had a standard pop-up flash so you could start playing around without all these gear headaches.
The simple solution is to buy a Canon 90EX flash.
It’s cheap (I paid about $50 on ebay), it’s small (it was designed for the Canon mirrorless camera system) and it gives you the equivalent of a pop-up flash on your pop-up-less camera.
The really interesting thing about it is that it can be used as a master trigger for the Canon optical triggering system just like the ST-E2. The slightly larger and more sophisticated 270EX speedlight can’t do that.
The 90EX is as simple as a flash could be: it has 1 power button, takes 2 AAA batteries and has no ability to swivel like a conventional speedlight. There’s a switch to lock it onto the camera but there’s no other buttons on it.
All of the interesting stuff is accessed through the camera in the “external speedlight control” menu option. Here you can set the flash to TTL mode (to act as a general purpose pop-up), manual mode (you specify the flash power setting) or you can enable the wireless optical transmission mode and start using it to trigger an external speedlight in TTL or manual mode.
Yes, this only triggers the Canon optical system but that will work with all of the larger speedlight units such as the 420EX, 430EX, 550EX, 580EX and 600EX-RT. Each one just needs to be flicked into slave mode and in the case of the new radio triggering flashes like the 600EX, you’ll need to ensure they’re in optical slave mode rather than radio slave mode. If you want, you can even use the 90EX as a trigger for 2nd curtain sync or high speed sync modes.
The 90EX can also be used as a dumb trigger for non-Canon flash units that have optical slave trigger (eg. studio flashes or Nikon flashes in SU4 mode). To use the 90EX as a dumb trigger, all you need to do is flick the 90EX into manual mode (to stop the TTL pre-flash), dial it’s power level down to the minimum (so it doesn’t contribute light itself) and start shooting. It’ll happily trigger any flash that can see it fire.
Yes, the 90EX can be simply used as a pop-up flash replacement but in my opinion, pop-up flash has to be one of the worst lighting sources for photography ever invented. It will do the trick when you’re desperate for some light but it won’t do it very well.
The Canon optical system isn’t perfect – which is why their radio system has been introduced – but if you’re just doing some basic off-camera flash shooting in your own home, the 90EX is likely to be completely sufficient for your needs. Yes, you might be able to find a 3rd party radio triggering system that will give you Canon TTL control but I doubt you’ll be able to pick up that for this kind of price. If you need a basic Canon trigger, this option seems like a bit of a no-brainer.
If you’ve found the above rant useful, you may like to sign up to one of my regular outdoor lighting workshops that I run in the Melbourne CBD. I run those through my meetup.com group Melbourne Photography Education.