Paul C. Buff, Inc. Technical Forum

Or, if you meter the main light and get, say, f/11; then meter both lights and get f/11'5, then your fill would meter about f/8 by itself (f/8 is half of f/11, so f/11 plus one half of itself would be f/11'5). Due to differences in how the light falls on the subject, this would only be an estimation.

If you are using a regular flash meter and if the slave flash has a test button, you can "arm" the meter and press the test button on the slave flash. When the meter senses the flash, it will take a reading. You will only need a way to supprot the meter at the subject's location.

This is extremely helpful. Thank you. I've looked at the strobist website but still couldn't find the answers I'm looking for.

So lets say I set my main flash (Alienbee800) to read 1/125 F8. Should I set my fill (slave) at 1/125 F5.6? Then what should my camera be set at....the main? Or do I measure both of lights together? :?

I did not see your last post.....sorry.

Yes, the additive properties of light will require you to meter both simultaneously.