Flash Duration - Please HELP!

[Puzz1e]

I'm pretty new to flash photography and have never used studio strobes. I have been researching for weeks and trying to figure out what studio flash system I want to invest in. At the moment I'm considering getting the Elinchrom 500 BXRI set. My plan is to later also get a single style RX1200 head to use as my main light when I need to overpower the sun etc and use the 500s as fill lights. Here's my issue:

- As I understand, the flash duration on the 500 BXRIs is different to that of the RX 1200
- I'm also under the impression that flash duration changes according to the power setting on the flash (with full power being shortest duration)

- Now if I want to shoot a studio portrait of an action shot with these three lights all at different power outputs...will the 500s (used as fill light) still cause motion blur even though my main light's flash duration is quick? Basically as I understand it, I will be bottlenecked to the slowest flash duration of the 3 heads when using them together. Is this correct?

Help would be really appreciated!

[Adrian Fischer]

I think the short answer is no. Depending on your camera your max shutter speed for flash is either 1/200, 1/250 or 1/500. The 500 flash will fire quicker than you shutter speed and freeze any action. Having said that, Im no expert although I do shoot a reasonable amount of studio flash for dance and cheerleading action shots.

[Invictus]

As I understood it when I last looked into it: Full power = longest flash duration.

[ameerat42]

As I understood it when I last looked into it: Full power = longest flash duration.

Correct, tick, right!

Puzz1e. When you say "overpower" the sun, you do mean that you reduce its effect on the exposure by the usual means of high shutter speed, don't you?
With the setup you described for the studio shot, any motion blur would come from too strong ambient light. You might, though, get multiple (fainter) images from the three light sources if they are not in sync.

[Puzz1e]

As I understood it when I last looked into it: Full power = longest flash duration.

That's for speedlights (eg Nikon SB 900). Studio strobes work the opposite way: full power = shortest duration

[Puzz1e]

Correct, tick, right!

Puzz1e. When you say "overpower" the sun, you do mean that you reduce its effect on the exposure by the usual means of high shutter speed, don't you?
With the setup you described for the studio shot, any motion blur would come from too strong ambient light. You might, though, get multiple (fainter) images from the three light sources if they are not in sync.

Lets assume I had killed all ambient light through shutter speed and aperture. I'm assuming if I have a multiple light setup, that I will still get motion blur if some of my strobes have longer flash duration than the others...

[ameerat42]

In the light of the post just before your last, I must really ask what sort of flash durations you are likely to be using, and what type of action you are photographing? Theoretically, there is always motion blur in a photo, it's a matter of whether it is noticeable or appreciable, ie, whether it is soaked up by the resolving limits of the system.

So it's down to what speeds are involved.

[snappysi]

I could be wrong but i am pretty sure also that the longer flash duration equals the strongest output iresspective of what exact type of light ????? and as to the freezing action question, i am not sure i understand exactly but the only thing that will stop the action is down to the flash sync speed, it is the shutter speed that freezes action, not so much the light......

i could of course be wrong

Simon.

[JM Tran]

I could be wrong but i am pretty sure also that the longer flash duration equals the strongest output iresspective of what exact type of light ????? and as to the freezing action question, i am not sure i understand exactly but the only thing that will stop the action is down to the flash sync speed, it is the shutter speed that freezes action, not so much the light......

i could of course be wrong

Simon.

You are wrong Simon, its not just the shutter speed that freezes the action, but the speed of the flash as well. If a strobe shoots at full power at 1000ws with a high shutter speed, it will not be able to freeze the fast movement as well as shooting it at the lowest power output. I dont wanna go into too much details as others can explain it better.

[Feg]

That's for speedlights (eg Nikon SB 900). Studio strobes work the opposite way: full power = shortest duration

Dont get how that would be possible.Surely any flash that dumps all its power would be longer than one that only dumps some of its power.

[Puzz1e]

Dont get how that would be possible.Surely any flash that dumps all its power would be longer than one that only dumps some of its power.

Monolight/studio heads work differently to speedlights. I'm not sure of the reasoning but its true.