Tom Reichner wrote in post #17541544
What about using a flash when shooting birds in rapid flight, or animals running swiftly, when I want to freeze motion blur? Doesn't "sync speed" keep one from using flash at the appropriate shutter speeds? Thru experience I have found that for most duck species in full flight, one needs to shoot at 1/3000th of a second in order to completely freeze motion blur in the wing feathers. How would a flash possibly help with that if it forces you to shoot at a ridiculously slow "sync speed".
Heya,
You can freeze the motion of a flying bird with flash at slow 1/200s synch speed quite effectively, if the flash is the exposure. If it's acting as fill (like what your friend is doing, just gentle fill to get micro-contrast on feathers, soften light, etc, but not be the source of overall exposure) then without enough shutter speed, it will certainly blur on a bird in rapid flight or just rapid motion in general. But if you're shooting in darker light, and at 1/200, F8, ISO whatever you would normally get a very dark underexposed photo, and flash becomes your exposure, you can stop motion because the exposure time will more be based on the time of the flash (which is of course extremely fast, so it will stop motion).
Kind of like how we stop the motion of super fast beating wings on bugs (bees and the like) in macro, since shutters cannot even stop that at 1/8000s, but a simple flash can do it with any shutter speed you care to use.
Very best,