Studio lighting shutter speed

[adjohnson]

Ok, so I've read here on the forums that shutter speed doesn't matter when it comes to studio lighting if the ambient light is negligible. After a lot of thought, it's starting to make sense to me. And I guess this is why my ancient flash meter doesn't have a shutter speed setting. Now, I have a new flash meter with shutter speed settings. Why does the new flash meter show different F-stops for different shutter speeds if shutter speeds don't matter?

Thanks for any help in my learning process!

[PacAce]

Are you referring to strobe lights or regular studio bulb lights? For strobe lights, which is on for a lot shorter duration than the shutter is open, shutter speed doesn't matter as long as it's at or below the sync speed it the strobe. However, with studio bulb lights which is on longer than the shutter is open, then shutter speed does matter. If you are measuring ambient lighting, then the aperture is most definitely dependent on the shutter speed and hence the many different values of shutter speeds for the different values of aperture (or vice versa).

[adjohnson]

I'm using strobe lights (Morris AC screw-in strobes). So all my studio lighting flashes - I don't have any constant lights except some basic room lighting that is negligible I think. In this case shutter speed shouldn't matter I think because I think these stobe bulbs are faster than my shutter speed (?). But my flash meter gives me different F-stops for different shutter speeds which doesn't make sense to me.

Thanks

[chris.bailey]

Shutter speed does not affect the exposure in flash photography. Think of the flash as a pulse of light. Its the energy in this pulse that sets the exposure as long as the shutter is open to expose the sensor for the full duration of this pulse. If the shutter speed is too fast, then the curtains are still travelling as the pulse finishes, leaving a dark strip on the right hand side of the frame.

I dont really know why a digital flash meter should have a shutter speed input and my Seconic does indeed require a shutter speed and gives different f values if you change it. I do most of my studio work at around 1/200th as I prefer to hand hold. i have found however that if I set the meter at 1/200th then the results are under exposed and I tend to leave it at the 1/60th setting.

I too would be interested to know why a flash meter should have a shutter speed input.

[Jon]

I dont really know why a digital flash meter should have a shutter speed input and my Seconic does indeed require a shutter speed and gives different f values if you change it. I do most of my studio work at around 1/200th as I prefer to hand hold. i have found however that if I set the meter at 1/200th then the results are under exposed and I tend to leave it at the 1/60th setting.

I too would be interested to know why a flash meter should have a shutter speed input.

Much studio work is done with cameras with leaf shutters (in the lens). These shutters, unlike the focal plane shutter we all know and love, expose the whole film/sensor plane at once. If your flash puts out a long burst, as some studio flashes do, changing the shutter speed makes a difference. You'll also see this if you use your camera and flash in FP mode (with speeds faster than 1/200-1/250 sec), where the flash has to fire across the entire shutter curtain travel time. As back in the good old days X-sync for strobes was at 1/60 sec., any shutter speed setting faster than that is assumed (for metering purposes) to be FP sync, and requiring some exposure adjustment for the shutter speed.

[adjohnson]

Thank you Jon for that explanation!!