quicky regarding studio flash setup

[AshleyC]

ok the question, why do you use studio flash's in manual mode? why not use the cameras TTL / iTTL or whatever to determine the strength of the light?

I ask because i had my first studio shoot at the weekend and really enjoyed it. But was just confused with the lighting a little. They were all set up and one guy did a light meter reading off them, f8 at 125. Which was great, got some good looking photos. But what would happen if i wanted a shallow DOF for a close up head shot maybe. If i opened the camera up to 1.8 or whatever it would of meant adjusting the flashes to the point where the light meter told me a good reading for 1.8? which would really break up the flow of the shoot. Why not just set the camera / flashes up in TTL commander mode or whatever its called and let it get on with making the decisions? The lights were all elinchroms i beleive. Is it just a case of studio flashes not being able to be controlled in this way?

And i guess another query regarding light meters, never used one and should of had a closer look on sunday tbh, but how do they work? Do you dial in your aperture and then test it against several strengths of flash until it tells you youve got the right strength set?

 

[Garry Edwards]

Hotshoe flashes are 'clever' in the sense that they can talk to cameras and vice versa, so the power can be controlled automatically.
Studio flashes are 'dumb' and it's the photographer who has to make the decisions. It's quick, easy and becomes intuitive, it really isn't a problem and doesn't affect the workflow.

Light meter - you just set it to the same ISO and shutter speed as on the camera (although the shutter speed makes very little difference), place the meter where the subject is, point the sensor towards the camera and fire the flash. The meter measures the light that will reach the camera and, on most modern meters, expresses this as the f number that needs to be set on the camera, e.g. f/8. Some of the simpler/cheaper ones express the reading differently, but it amounts to the same thing.

 

[Michael Sewell]

Once you've used the studio lights for a while, you get a feel for adjusting the light level to accommodate a change in aperture. Meter to set up, and then take it from there.
No different to adjusting your aperture for a shift in light levels in an ambient shot

 

[AshleyC]

ok thanks, i get that with the lights being "dumb" now But the query is still there with the f stop. Do the meters have a shutter / aperture priority like camera then? If i set it to f1.8 and the iso to 100 say would it tell me the shutter speed instead?

*edit* just saw your 2nd resp. So i guess its trial and error to a point and just getting used to how your lights work with certain apertures. Which is fair enough, just need more experience

 

[Michael Sewell]

Nah, it ain't trial and error at all.
Going from full to half power on a lighting head reduces the effective light on the subect by one stop or 1EV. If you wanted the subject to be exposed exactly the same, you would open the aperture by one full stop or 1EV ie, going from f8 to f5.6.
Actually, the lighting manufacturers make it very easy for you. You normally find two dots between each setting on the heads with analogue dials. If your camera is set to have adjustments made in 1.3rd stop increments ( or 0.3EV), then each dot represents one click of your adjustment dial.

As for shutter speed, it has no real effect on your exposure where the flash is providing all, or most of the light, as the duration of the flash is much shorter than the duration of your shutterspeed, and it's the light from the flash that makes the correct exposure.
The shutterspeed comes into play when you are matching your flash output to the ambient levels, and you want to reduce the effect of the ambient light by increasing the shutterspeed. But that's whole 'nuther ball game!