[philbaum]

We know that a portable strobe, such as the Cactus RF60 that i have will perform at least 1 full power flash because its rated and tested at that.

So my thinking is, what if i reduced power levels to some fractional amount less than 1:1 full power, could i do high burst rate shots. So i reduced power to 1:16 and did a 3 burst shot with flash. All 3 came out perfect. Then i increase power to 1/4 and all 3 came out pretty close to the same power. Then i increased power to 1/2 and made 3 burst shots. 2 shots were adequately illuminated but there was no third flash. And there was a slight decrease in light level between the first and second shot.

I have a shoot schedule for 5:30pm with 3 actors and 2 dogs for a dinner theatre promo shot. Don't know what the dogs are there for, but i'm thinking multiple shots might get me a higher chance of a successful image.

[derekkite]

We know that a portable strobe, such as the Cactus RF60 that i have will perform at least 1 full power flash because its rated and tested at that.

So my thinking is, what if i reduced power levels to some fractional amount less than 1:1 full power, could i do high burst rate shots. So i reduced power to 1:16 and did a 3 burst shot with flash. All 3 came out perfect. Then i increase power to 1/4 and all 3 came out pretty close to the same power. Then i increased power to 1/2 and made 3 burst shots. 2 shots were adequately illuminated but there was no third flash. And there was a slight decrease in light level between the first and second shot.

I have a shoot schedule for 5:30pm with 3 actors and 2 dogs for a dinner theatre promo shot. Don't know what the dogs are there for, but i'm thinking multiple shots might get me a higher chance of a successful image.

I was doing repeated 3 bursts with 5 flash units, iirc about a 1.5 seconds between bursts. I could do three bursts of three then had to wait a bit for everything to get going again. 1/16 power, Yongnuo 560III with duracell rechargables. The bursts were quite quick, I think my exposure was half a second or 3/4 second. I don't remember all the details, but yes, it is possible.

If you are triggering multiple flashes at 1/16 you can maintain a slow continuous mode for maybe 9,10 shots. Mid mode would do three shots with a rest between.

I think the choke point is the batteries. The flash units didn't delay to cool down, but I think the batteries got hot and the discharge rate dropped. The flash unit safety for overheating takes 30 seconds or so to reset. The green charging lights were on, maybe 10 seconds or so. The batteries were very hot if removed at that time, hot enough that I couldn't hold them in my hand.

[UncleVanya]

The batteries were very hot if removed at that time, hot enough that I couldn't hold them in my hand.

Yikes!

[MJSfoto1956]

FWIW, burst flash (and even burst bracketing with flash) can definitely be done with an LED flash system (validated by me) -- however, LEDs are currently only powerful enough for close up work. Still, this may prove to be useful for certain use cases.

Michael

[mcgregni]

I can get continuous flash shots from both my AF-540FGZ Mk1 and MkII models on the K7 .... From 1/16th power and below I get continuous firing at about 2.5 FPS up to 15 shots ( that's the K7 buffer in RAW). I have tried 3 of these in succession and have not felt any heat on the flash.

[Class A]

So my thinking is, what if i reduced power levels to some fractional amount less than 1:1 full power, could i do high burst rate shots.

Sure. Less powerful flash power means less energy is taken from the capacitor which leaves more energy left for subsequent shots (and a shorter time to fully recharge).

You could increase the recycling speed of the RF60 in three (and a half) alternative ways:

1. Use two (or more) RF60 in parallel. For instance, two RF60 at 1/4 power will emanate the power of a 1/2 flash, but at the recycling speed of 1/4 power.
2. Use a powerpack. Cactus offer their own, but any with a Canon powerpack plug will work.
3. Use a V6 and enable group cycling. Then you can either alternate between two RF60 or between four RF60 respectively. By changing the flash that is used for illumination for each shot, you allow the other inactive flash(es) to recycle. This approach also helps combating potential overheating.
4. The RF60 also has a "quick fire" option that allows the flash to fire even though the nominal capacitor level needed has not been reached yet. While this may enable you to get a shot you otherwise would have missed, waiting for the flash to recharge sufficiently, it also means that you will have to deal with some level of underexposure. Because of the latter, I leave "quick fire" turned off per default.

[SOldBear]

Try something like Quantum QFlash with Quantum Turbo battery pack. I once fires about 100 full-power flashes, about 1 sec - 1.5 sec apart without any problem.

I figure if the flash power were set at 1/4, I could fire as fast as the camera allowed.

[philbaum]

Thanks for all the suggestions. Never dreamt that there are so many ways of cooking this. I didn't have any problem with the few burst shots i needed, but slowing it down with a med or slow rate would probably have worked even better for the shot variety plus some recharging ability. Thanks again.