Which Speedlites and external flashes can be used with Canon T5

[filmninja37]

Hey guys!

New guy here. So I've been trying to figure this out on my own, but I haven't found a solid answer -- which is why I'm here. I have a Canon Rebel T5 and I've been looking at getting an external flash (or two) to use with it. I read somewhere that this camera does not have an internal speedlite transmitter, and that you cannot use it with external (off-camera) speedlites. I would just like to clarify what speedlites (both Canon and third-party) can be used with this camera (on-camera), and if eTTL is possible. Also, I would like to know if there is any way to use an external (off-camera) wireless flash (or two) with this camera, and if THAT would be possible with eTTL.

Sorry for the long question, just trying to clear things up!

Thanks so much!

Michael

[jrhoffman75]

It doesn't have a wifi wireless transmitter, but it can fire an off-camera flash using the optical wireless method.

This is from the T5i manual, but yours will be similar.

[filmninja37]

Hey jrhoffman75,

Thanks for the quick answer, I think I understand a little better now.

Michael

[TCampbell]

That manual page entry is for a T5i but I think the OP indicated they have a T5 (without the "i" suffix).

I seem to recall that T5 cannot work in wireless master mode to control off-camera flash using it's built-in flash and requires an external flash.

Canon flashes that can be used as an on-camera "master" to control off-camera flashes include

1)  Speedlite 90EX (a somewhat low-power flash but can be used as a "master" to trigger off-camera flashes)

2)  Speedlite 430EX III-RT  (note that the less expensive 430EX II cannot control off-camera flasehs... it must be the "III")

3)  Speedlite 600EX-RT (this is Canon's flagship speedlite flash... it does everything.)

Canon also has the ST-E2 and ST-E3-RT on-camera transmitters.  The ST-E2 is "optical" and the ST-E3-RT is "radio".  That means the ST-E3-RT only works with radio-equipped flashes (currently only the 600EX-RT and the 430EX III-RT) and the ST-E2 can work with any Canon Speedlite that supports remote "slave" mode  but optical does require an unobstructed "line of sight" between the transmitter and slave.

The model number is a clue as to power of the flash.  If you eliminate the trailing "0" from any model number then the leading number(s) indicate the "guide number" of the flash as measured in meters.  E.g. a 430EX III-RT has a guide number of "43" and a 600EX-RT has a guide number of "60".  

The guide number is the distance at which that flash unit can provide adequate lighting for a subject ASSUMING the camera is using ISO 100 and the lens f-stop is set to f/1.0.  You'll notice that ISO 100 isn't a problem, but no lens made today supports f/1.0.   While you might think this makes little sense, they do this because it sets a baseline.  It turns out if you merely divide the guide number by the focal ratio you will ACTUALLY be using, the result is the distance that your flash can support.

For example.... suppose you use a 430EX III-RT with a guide number of 43 meters (141') and you are using your kit 18-55mm f/3.5-5.6 lens at f/5.6 and ISO 100.  You would divide that 43 meters (141') by 5.6.  That works out to 7.7 meters or about 25'.

Meanwhile the 90EX is 9 meters (29') at f/1.0 and at f/5.6 it's 1.6 meters or just slightly over 5' (not very far at all).  But that's at ISO 100... if you shoot at ISO 400 then all the distances double and the 90EX can handle about 11' (still not a lot of power.  The 90EX is mostly useful as a trigger more than as a key light.)

All of the math assumes straight-on non-modified light.  If you use any type of diffuser, reflector, shoot-through umbrella, or "bounce" the flash off a surface... all that eats a percentage of light.  You can quickly see why it's handy to have powerful flash units when you plan to use modifiers to control the light.