> * This is not a bounce question, but it is an Elan 7/420EX question. Let's say I want to use flash as the primary light source. But I also want to control the aperture. So I set the camera to M mode and set the shutter to 1/125 and the aperture to the desired opening. Question: how do I know if the flash is powerful enough to do this? It is my understanding that, in M mode, E-TTL will control the flash power such that the selected aperture results in a correct exposure. But the meter is just flashing -2 underexposure on my camera at 1/125@f/8 in a small room. The flash should be powerful enough to do that exposure, right? But what if I asked for an aperture of f/32. Will the camera or flash tell me that it is not powerful to correctly expose at f/32? Yes, I have read the flash FAQ, and it does not specifically answer this question. >
I think in this situation, your settings in M mode control the ambient exposure, and the flash exposure is calcluated automatically by the ETTL system. That is, you can set whatever aperture and shutter speed you want, and the flash exposure will remain the same--changing the aperture/shutter speed just changes the exposure of the background, and has no effect on the flash exposure. Someone correct me if I'm wrong, but I'm pretty sure that's how it works. --Alex * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
