I got a pair of "no name" strobe lights with a simple hot-shoe trigger and trying to use it with EOS 550D. Although it seems to work at first glance (strobes fire when shutter is triggered) in fact they don't make any difference to the picture.
Camera is set on Manual mode - 1/125 F1.8 ISO 100 - and both with the strobes on and with them turned off the image is exactly the same.
I suspect they fire too early or too late, not when the curtain is open. I have disabled red eye correction but can't do much else in the Flash control menu - all the menu items are disabled because the hot shoe trigger is not a Canon brand I suppose.
Any ideas or pointers to what could be the problem and how to set up the camera for use with strobes?