Studio flash shutter speed setup

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Bugler77

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Hi, after some info here. If I can first explain my understanding of studio flash then if someone could reply confirming my understanding and help with my question about shutter speed.
My understanding is that the power of the flash alters the aperture but you shutter speed on camera does not have too much impact as long as its within you cameras flash speed sync parameters? If this is correct then the shutter speed is actually adjustable by the flash duration. How do I adjust the flash duration I have elinchrom bxri 500 heads.
The basis of this question as a want to photograph some movement but not too sure how the adjust shutter speed to capture it how I want it.

Thanks...
 
I'm not sure that I understand your question but...

Primarily, the sole function of the shutter, when using flash, is to be fully open when the flash goes off. So, if the shutter speed is somewhere around say 1/60th - 1/125th you can be pretty sure that the shutter will be fully open and that it won't be open for long enough for any normal level of ambient light to affect the shot.

However, at say 1/250th second, it may or may not work, depending on the camera, radio trigger and luck. At 1/4 sec, it definitely will work, but you will very likely get light pollution from ambient light, and camera shake will show up.

Effectively, the flash duration is the shutter speed.

You can't adjust the flash duration, or at least not really. There is some room for 'adjustment' because if you reduce the power on the studio flash, the duration becomes longer, but you won't get a great deal out of it.

So, what you can do is to either use continuous lighting (the modelling lamps in your flash) or, if using flash, have the modelling lamps on too and use a longer shutter speed to create a bit of blur, contributed by the continuous lighting.
 
The flash duration of a large majority of studio flash heads is very short indeed, and is not adjustable. (though that duration is usually changes somewhat with the power setting... It takes slightly longer to discharge higher settings)
The elinchrom 250 heads give 1/2762 sec and the 500 1/1558sec..
This is excellent to stop motion, but is no help at all to give blur.

The normal practise is to use the Power and aperture to set exposure .... but if there is a lot of ambient light as well, You can adjust the shutter to give the correct exposure for the ambient light, but must not set shorter than the shutter is synced for, usually in the region of 1/250 sec.
 
Thanks for the replies guys, I will have to use continuous lighting for what I want to do
 
The flash durations that Terry quotes are t.5 times. They don't bear much relation to reality - lots of debate on that on here over recent months.

Having tested the BX-Ri500 fairly thoroughly, I can tell you that its flash durations equate to actual shutter speeds of around 1/900sec at full power to 1/700sec at min. The BX-Ri250's smaller capacitors are usefully quicker, ranging between 1/1300sec to 1/900sec.

Elinchrom BX-Ri heads are among the fastest studio units available at the more affordable end. Some have durations that are twice as long at similar power outputs.
 
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The t.5 or t.1 figures are just points on a sinewave. Neither is better or worse than the other They just show different slices along the path of of going to full intensity and falling to zero. the T.5 shows the slice that is above 50% of the highest intensity and the t.1 shows it where is is above 10% of its highest intensity. neither completely stop motion.

In a way they have much the same characteristic as a bladed shutter at full aperture, that is only fully open for a fraction of its opening time.

Neither gives a meaningful accurate measure, rather they give a very practical one.

(At least neither gives the obvious rhomboidal shaped image to a fast moving object taken with a slow traversing focal plane shutter, as seen at high shutter speeds on an early Contax or Speed Graphic.)

The truth is, nothing is "Perfect" in the world of Photography, we either live with the deficiencies, or learn to take advantage of them.
 
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Terrywoodenpic said:
The t.5 or t.1 figures are just points on a sinewave. Neither is better or worse than the other They just show different slices along the path of of going to full intensity and falling to zero. the T.5 shows the slice that is above 50% of the highest intensity and the t.1 shows it where is is above 10% of its highest intensity. neither completely stop motion.

In a way they have much the same characteristic as a bladed shutter at full aperture, that is only fully open for a fraction of its opening time.

Neither gives a meaningful accurate measure, rather they give a very practical one.

(At least neither gives the obvious rhomboidal shaped image to a fast moving object taken with a slow traversing focal plane shutter, as seen at high shutter speeds on an early Contax or Speed Graphic.)

The truth is, nothing is "Perfect" in the world of Photography, we either live with the deficiencies, or learn to take advantage of them.
Click to expand...

All true Terry, but the problem is that folks read 'flash duration 1/XXXXsec' and, not unreasonably, assume this to be have the same action-freezing potential as a similar shutter speeds, when it's actually miles off.

The common rule of thumb, that not many people know about or understand, is to take the t.5 time (if you can find a reliably quoted figure) and multiply by 3x to get the t.1 time that is more comparable to real shutter speeds.

But actually that doesn't work either. For example, and since I can't find max and min durations for the Elinchrom BX-Ri 500, let's take the new Elinchrom D-Lite One that I've used a lot. It claims t.5 of 1/2200sec at max power and 1/1100sec at min, so using the 3x trick that would translate to 1/733sec and 1/366sec.

But when compared to actual shutter speeds I would estimate it to be the equivalent of around 1/900sec, and it doesn't vary significantly from max to min. There are very slight changes in the nature of the blur, but nothing that you could possibly distinguish in real use.

It's not an easy nut to crack, and hot-shoe IGBT-controlled flash gun's t.5 durations do actually (usually) work out very close compared to real shutter speeds, which just adds more confusion for the uninitiated.

PS Your comment about leaf shutters is an interesting one too! Fortunately not a problem we have to deal with much these days, though the Fuji X100 throws up some unusual effects ;)
 
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