I've always wondered, how much light/power output is given by pressing the test button? It certainly isn't 1/1 or 1/2, on my 430EX (mk1) I can press it a few times in a row without losing so much charge that it has to stop to recharge (battery-dependent, of course), so i'm guessing around the 1/64 mark. Can the higher-model speedlites be programmed to output a certain power from the test-button?