Flash/Light Meter simplifies lighting

I think anyone using studio strobes will greatly benefit from a flash meter. Here is the older Sekonic Meter I use most of the time. 

The primary thing I use the flash meter for is getting the exposure for my subject. I always start here when shooting. The light I am measuring is the main light, because it is lighting my subject, not because of how bright it is.

Once you have this reading you can then take other readings. If you have two lights hitting the subject as in this photo below I wanted to control the contrast in the photo and using a flash meter was very helpful.

This is Masha, one of the School of Photography 1 students I was teaching in Hawaii a couple weeks ago. She was my model as I taught the class how to ratio lights.

In a very classic lighting setup like this the main light is 45º to the axis of the camera and subject. The second light is one the same axis as the camera, which is perpendicular to the background.

I took a reading first of the main light that is 45º to the right of the camera. ƒ/8 was the reading for the main light on ISO 100 and sync speed of 1/250.  I turned this light off and then worked at setting the second (fill light) behind the camera to ƒ/5.6, which is 1/2 the power of the first light.

Once this was set I turned both the lights on and took another reading and the combined ƒ-stop was ƒ/9.

Taking reading of the background for the top photo of the soldier

When I made the photo of the soldier I knew I wanted the background which was white to be two stops brighter than the subject. The subject was ƒ/16 and therefore background is ƒ/32.

Some people prefer to getting a reflective reading off the background, but either way the reading needs to be two stops greater than the subject.

Many photographer will measure the background with the lights on it at full power and then set the main light on the subject by under exposing by 2 ƒ-stops.

For the portrait of Masha, I had a black background and put a blue gel over the flash and metered the background to be 2 ƒ-stops under exposed as compared to the subject. In the photo of Masha the background was just a tad brighter than ƒ/4, which was 2 ƒ-stops darker than the ƒ/9 of the two lights combined hitting her face.

You can do all this using your histogram, but lets just say the explanation of how to do it is a lot more complex than this for using the flash meter.