The biggest challenge you will have is recycle time. Without a doubt, you would have to use an external battery pack (it cuts recycle down to a 1/3). Don’t go with a 3rd-party knock-off. Use the Canon external battery pack. Doing so will reduce the risk of overheating. My advise is to have a runner friend come over and do a series of test shots. Switching your Speedlite into high-speed sync will automatically shut the power down into the range that you are already considering. It has to do this because in HSS, the Speedlite turns on and off 30,000+ times a second. yet, the power consumption is similar to that of a 1/1 shot. Also consider shooting with with two or three or more Speedlites, instead of just one. Then the Speedlites will fire at a lower power setting and you’ll get an even faster recycle time. You can rent Speedlites and power packs for a very reasonable price from BorrowLenses.com.

I am often hired to shoot at the finish line at running events like marathons and triathlons. It’s not unusual for me to shoot 5,000 to 7,000 images, rapid-fire style, in the span of 4 to 6 hours

The runners often wear hats which cast a shadow under their eyes so I would like to use my 580EXII as fill.

Would it fry my 580EXII over the course of 4 to 6 hours? (I have fired 3 shutters in 2 years as a sports shooter, so I am weary of frying more gear).

I was thinking of using it in manual mode, using high-speed synch, but powering down the flash to 1/8th or 1/16th power to save on both battery life, recycle time and to not fry the flash unit.

The runners are typically about 10-15 away from me and I need to use a shutter speed no slower than 1/500th to stop motion.

Daylight conditions will change through out the shoot. From cloudy and sometimes rain in the morning, to blazing sun in the afternoon.

Please let me know how you would approach this.

Thanks for any help. It is much appreciated.

Vivian

Thanks for the quick response. But what you are saying here seems to be contrary to what you said above in the article:

“I think of the amount of the flash as the duration of the flash. A speedlite ["speedlight" in Nikonese] firing at full power emits a longer burst of light than it does when firing at quarter power.”

This seems to imply that flash will always light with the same “brightness”…only the time duration changes when you adjust the power level.

Praveen.

Great question! You’re missing the fact that the flash power can be dialed up or down by camera through FEC. The speedlite can fire in High-Speed Sync at full-power. It can also fire in HSS at 1/2, 1/4, 1/8, 1/16, 1/32… Keep in mind that the effective range of a speedlite at any power level in HSS is substantially shorter than it is in standard mode.

I am just learning about high sync flash. One thing that I didn’t understand from your article: During high sync, if the flash is “constantly” on during the the time the curtain slit travels across the sensor, and if the light level produced by the flash is constant during this period, then how does the FEC work? Presumably, during normal (non-FP) flash, -FEC would reduce the duration of the flash and +FEC would increase the duration of the flash. However, during FP flash, the duration would be fixed by the shutter speed…..what am I missing?

Praveen.

I’m getting to the party late but I rediscovered your blog after meeting you last week at Joe’s One Day Lighting Seminar. Sorry for almost blinding you with the 3 580EX IIs.

My question is regarding your statement about HSS. “On Canon 580-series or 430-series speedlites, your flash must be set to ETTL mode.”

I could be mistaken but I’m pretty sure that I was able to set off 3 580EX IIs as slaves in HSS with another 580EX as the master in manual mode. I’ll test it again this week just to make sure.

Will