Daniel wrote > Yes. I think interpolating between the FP and the standard mode > is flawed. At full power, if the flash took 1/60th of a second, > then flash sync at 1/250th, the shutter would be limiting the > exposure, which it isn't. The slowest a portable flash unit ever > fires is something like 1/1000. At fastest, about 1/10000. > Studio units are usually fixed at about 1/1000, which is nice > because it doesn't cause a failure of the reciprocity effect. > 1/10000 can, but I've never noticed. But then again, I'm not very > picky. I agree I was wrong. Now if the flash fires 1/1000s, what remains mysterious to me is why does the guide number drop from 42 at 1/60s to only 20 at 1/250s? If the flash duration is maximum 1/1000s, why couldn't the flash give the same light power in both cases? > I don't see any way to do that. I have only the camera and the > quick reference with me, not the full manual. The full manual didn't help me more... Thierry
