Thanks Mt Spokaine, am I correct in saying that the black focus points (which my 5D has ) light up & indicate the point of focus by lighting up red to confirm focus (which is what the 5D & 580ex does) so is the issue that it is still the same system as the origional 5D ? or has something else changed that I'm not aware of. My appologies if you have already explained this & I'm not understanding. At present at receptions & low light my method is to only use the center focus point which is assisted well by the IR beam.many thanks Peter
There is a short red flash which happens after the camera has achieved focus. When using one shot focus, the camera will not open the shutter until focus is achieved. My point is that focus is achieved well before the light flashes, and I always get a sharply focused image by just doing a full button press.
Note: If You use AI servo focusing, the camera will fire as soon as you do a full button press, and you will get oof images. This is user error, don't use AI servo in extreme low light.
Many of the issues that are posted about are the result of incorrect camera settings.