If you want to do “studio type” shooting, set your flash power manually. On strobes you have to do it that way; on speedlights you can. Then use a flash meter.
How? Here’s how.
- Set your camera to the desired settings. For instance, 100 ISO, 1/125th second, and f/8. These are pretty typical studio settings.
- Verify that a shot taken like this without the flash is all black. That means ambient light will play no role. If not, go to 1/200th second.
- Now set up your flash or flashes. Set the power to, say, quarter power for a start – or whatever you think might be roughly right. With experience, you will get this just about right.
- Holding down the the MODE button, set your meter to flash metering mode (the lightning symbol; not the sun symbol, which is ambient metering). Your meter now reacts only to flash.
- Set the meter to 100 ISO and to 1/125th second (if those are your desired values).
- Hold the meter, with the white dome extended, where the subject will be.
- Reset the meter with the side button – it now reads “0″ for aperture.
- Fire the flashes.
- Read the value. If the value is higher than f/8 (eg f/11), reduce the flash power or move the flashes away. If the meter reads lower (eg f/4), then increase the power or move the flashes closer.
- Repeat steps 7-9 until the meter says f/8.
That is how you meter a studio, type shot like the one above. I usually meter each light separately and allow for that (e.g. two lights that both say f/5.6 will give you a total of f/8, if light from both hits the subject.).