I'm trying to improve my autofocus on macro and especially supermacro shots. I shoot a lot in dark water, and I've had really inconsistent focus. I tried a liittle UK pocket light, but the beam seemed too narrow. In the past, I've done some shooting with my dive light on the subject. That seems to get me a brightly illuminated subject with black all around the focus area. I don't really want to spend $3-400 for a specialized focus light. Has anyone done this with a Q40 or similar light? Will I end up with hot spots or a black background shooting ttl? Which is better, led or regular incandescent bulb?