I just ordered a used but working Canon ST-E2 speedlite transmitter because it was so cheap that it cost practically nothing. However, the ST-E2 hasn't arrived yet. My flash has support for ST-E3-RT as well. My camera doesn't have the "easy wireless" flash, meaning ST-E2 is necessary for this camera model.

How long is the range of a Canon ST-E2 transmitter in practice (not in optimal conditions)? I understand that it uses infrared. Is the infrared so powerful that it can bounce off walls indoors? How about outdoor shooting, does a ST-E2 work well outdoors?

Does ST-E2 require line of sight when shooting outdoors? If a flash is situated behind the camera in outdoor conditions, will it trigger? If not, is it possible to put some kind of reflector (umbrella?) in front of the camera but still outside the field of view to bounce infrared backwards?

At least my Canon flash has the sensor in the front, but fortunately the head turns 180 degrees, so I can always position the sensor in such a manner that it's facing the camera.

The reason I'm wondering is that I ordered a new ST-E3-RT which is taking quite long to arrive (the shop where I ordered it from still doesn't have the product, and it will take 2 weeks for them to have it in stock), before finding the used ST-E2. If it seems ST-E2 is enough for most conditions, I could cancel the ST-E3-RT order the cost of which is approximately 5 times the cost of a used ST-E2.

Apparently, professional photographers used infrared triggers for a long amount of time until Canon created a radio based system, so it can't really be that bad, right?

As another benefit of ST-E2 apart from the price, it works with older Canon equipment, meaning I can order used flashes which are quite decently priced when compared to new Canon flashes. As third benefit, it saves 50 grams of weight compared to the radio model.

  • 1
    \$\begingroup\$ There’s a lot of fluff in this question. Do you mind editing it down to the question and the details that matter? \$\endgroup\$
    – OnBreak.
    Mar 25, 2019 at 2:51

1 Answer 1


It works reasonably well -- much better inside because the light can bounce around to reach the flashes. Range really depends on whether flashes have line-of-sight to the ST-E2. I'd say 30-40 feet from memory.

I have not used it much outside. Wireless is super convenient outside if you have it. In its absence, and over longer distances, I much prefer a long TTL cable. Low tech and therefore super reliable, and also super cheap: you can buy a 33 foot-long Canon-compatible TTL cable for $35 on Amazon. You can go for hundreds of feet if you need to (though likely a niche usage given light falls off with inverse square of distance) by daisy-chaining them together. And a cable will always work when the flash is inside a modifier like a softbox, like wireless.

You are going to find that using modifiers is the key to making good flash photography. With infrared you are largely confined to modifiers like umbrellas where the flash can be angled to face the camera (either shoot-through or bounce) and sits outside the modifier. You just can't do that with modifiers like big softboxes.

If the flash is behind the camera, a cord is also a really good and cheap solution.


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