Motion blur with flash, why?
Hi,
I've been using my flashes for a while, but today was the first time I shot something moving fast (a girl dancing). Some of the pictures seem soft because of motion blur, in particular the hands that move fast, although I always thought that the flashes were fast enough to prevent this!
Basic setup was rather simple, two Elinchrom D-Lite 4 it with umbrellas, the 5D2 in full manual with 1/100 exposure time which guarantees to not miss the flash but is fast enough to give me a black picture from only the not very bright overhead lighting.
Are the flashes not as fast as I expected, or is it that the two of them don't fire exactly at the same time (triggered wirelessly with an Elinchrom SkyPort Eco trigger), or is there anything else I might be doing wrong?
Thanks, Colin
Motion blur with flash, why?
There are two ways for a flash to output less than full power. Generally speaking, monolights achieve lower output by reducing voltage to reduce the light intensity, meaning no change in duration. Speedlites achieve lower power by reducing the flash duration. That means a Speedlite at lower power is great for stopping action (and why hummingbird shooters use a group of several Speedlites at low power to get enough light with that short duration). A monolight is generally not a good choice for stopping action. There is an affordable exception - the PCB Einstein 640 has an 'action mode' that allows reduced duration. See this:
http://www.robgalbraith.com/bins/mul...=7-10053-10715
Motion blur with flash, why?
Exactly. It's just that with most monolights, reducing the power doesn't reduce the flash duration all that much...
Motion blur with flash, why?
Quote:
Originally Posted by
Colin500
As far as I understood for speedlights the duration goes down with the power, but not for monolights like I am using, which might even be fastest at full power...?
For many monolights, that's true - the lower voltage actually spreads out the peak, meaning a longer duration (slightly) at lower power.