blinded wrote in post #5790633
If you try to FEL button, it will only hold (without telling you how much too) if you don't review any images you take after using it. It also goes off if you decide to change any settings or even just not look in the viewfinder long enough.
I have a 1D2, and there are a few things you should know / can serve as workaround:
Set the review to come up automatically after you've taken a shot. I have mine set to 2 seconds, and I can see whether or not flash exposure is about right or not. If it's about right (which I would suppose it to be when using FEL; I'm doing the thinking in that case), I can keep on shooting with the same FEL.
FEL values are stored for 16 seconds by default (At least in a 1D series).
I have my "16 sec timer" set to 30 sec. (And my "6 sec timer" (AEL, VF info on in other situations) to 2 sec.) This is PFn 23.
So an FEL is held for 30 sec. In which time I can adjust aperture and shutterspeed to whatever I might want. (VF info on flash level even gets update if I stop the aperture down too far for correct exposure with a full flash: It'll indicate underexposure, and the flash icon will blink.)
Obviously, I cannot change shooting mode or ISO, but I cannot think of a reason why I would do that *and* need to keep the FEL locked
What if you don't have a 1D series?
CFn4 cannot be used, except on a 10D (and 40D?). This is a drawback IMO.
But again: (AFAIK) FEL values will be stored for either 16 or 6 seconds (not sure), and at least as long as shutter button is half-pressed.
If you don't want, or for some reason cannot keep the shutter button half pressed (for instance because you are changing shutterspeed or aperture), simpley press the DoF preview button (be sure to set the flashes CFn so that the modelling flash doesn't fire then!)
For as long as you keep the DoF button pressed, all timers are locked.