Paul C. Buff, Inc. Technical Forum

I'd like to play around with capturing moving objects. Is there any way to set up an Einstein to repeatedly strobe at a particular frequency? Could I set up an SB900 to stobe and trigger the optical sync on the Einstein?

Thanks in advance,
Corey

That would be the easiest way, using a speedlite. Depending on the speed, you will have to adjust power for consistent output. 40Ws should work out to about 10Hz with good consistency.

I believe you can do this with Einstein and PW as a trigger.

The Multimax can do a strobe mode; I don't think the TT5 system supports it, don't think it will even transmit the built-in Canon function.

I've been wondering... if I'm doing a single shot, not continuous... then I should be able to use about 640ws of power over multiple pops, no? ie, 4 pops at 160ws, as fast as it can be triggered? or 10 pops at 64ws, etc. Does that sound reasonable?

No. Unlike speedlites that use the capacitors as a "resivoir" that starts as full then dumps what it needs, leaving more energy for the next burst, Einstein fills to what it needs, then dumps.

I have to correct Tech here a bit. This statement is not correct

"No. Unlike speedlites that use the capacitors as a "resivoir" that starts as full then dumps what it needs, leaving more energy for the next burst, Einstein fills to what it needs, then dumps."

Actually, Einstein does just what a speedlight does . . . the capacitors are fully charged and when either is flashed at reduced power, only the amount of charge needed is used and the rest remains.

So, indeed, if you set Einstein to 160WS and flash, 3/4 of the initial charge remains and you can immediately take a second shot. So you can shoot four immediately consecutive flashes with the light set at 1/4 power.

However, with either speedlight or Einstein, doing this will result in a slight lowering of exposure during the progression of the four flashes because the processor determines the power of each flash by the length of the resulting pulse. Since the capacitor voltage in this scenario is dropping with each flash, but the time is the same for each flash, the exposure value progressively falls.

How much exposure change you will get depends on the firing rate and power setting. Remember, the capacitors are being recharged during the progression, and they recharge faster than a typical speedlight. For instance, the recycle time at 1/5 power (128WS) is about 1/3 second, thus you could fire at 3fps all day long with no exposure change from to flash. But at 5fps you would see some progressive exposure loss. At 8 FPS you would seem more exposure loss from the first flash to the last.

At 80WS the recycle time is about .21 seconds, so you could shoot at 5FPS with little if any exposure loss. If you shot at 80WS at 8FPS you would get pretty good results for a burst of 6 or 8 flashes. By dropping to 40WS you could shoot long bursts of 8FPS shots with little if any shot to shot exposure change.

An excellent example 10FPS strobing at 20WS can be seen in Rob Galbraith blog at this link:
http://www.robgalbraith.com/bins/multi_ ... 0053-10715

Thanks... I've shot some stuff using the continuous shooting specs, but want to shorten the interval for a single shot; I figured "640ws total" would be a useful starting point, and expect real-world yield to be a little less. I use it for effects like motion trails in long exposures, so evenness isn't critical. Just looking for more power than a 580EX in Multi mode, and to use it with studio modifiers.

The fastest rate that Einstein can fire is 12 pops per second. This is probably too long for motion trails . . you'll get multiple exposures rather than blur.

Well, what I'm getting is pretty close, so if 12 shots/sec is the limit, I'll work within that. I've been doing some stuff with drummers, one flash to freeze the head/body, a gridded strobe on the arms/hands.

Interestingly, I shot live without flash the other night, and saw some nice strobe effects from the LED stage lighting; a 1/20th sec exposure caught 8-10 distinct drumsticks.

How long can this be sustained? I have been bouncing around the idea of making a circuit to go stroboscopic after it is triggered. I would want to make sure it didn't fire too long.