I try to avoid using my flash if at all possible but, now with having a macro lens, i'm finding myself wanting to use flash more. Simple question here, how the heck do I meter in manual mode when using flash? I think the 'standard' flash metering is f5.6 at 1/60 shutter speed. Do I simply do the appropriate math as needed to re-meter for slower faster shutter speeds (ie: f8.0 at 1/30 shutter speed or, on the other side, f4.0 at 1/125 shutter speed)? Any basic information would be great! Thanks.