Just a tip for ST-E2 users. You could extend the range outdoors by using regular aluminum foil as a reflector. Here are some pics of how I attach a small piece to my softbox stand by simply wrapping one end to the softbox bracket. Just orientate the reflector foil according to the position of the ST-E2 such that the foil acts like a parabolic reflector. You could even turn the IR sensor of the speedlight away from the ST-E2 and it will still work reasonably well. Give it a try.


