Using a Light Meter – The Short Story

Basics of Metering – The Simple Truth

I just received an email from a reader who is experiencing some confusion about how to use her light meter to calculate a lighting setup.

I have written several lighting tutorials, like this one on Low Key Lighting, but this seemed like a good opportunity to do a little refresher course for everyone. To set the stage, here is the email from my reader, Sharon:

Hi Deborah,

Please can you help me with metering in the studio.

See below, totally confused and getting orange skin tones?

Incident light meter reading, from the subject point the meter at each individual light (all lights on), main, fill, rim, back lights ? Please can you give example, of each lights aperture and what I would put in my camera, aperture to use?

Or from the subject, point the incident meter towards the camera with all lights on?

Many thanks,
Sharon

What Are We Trying to Light?

Using a Light Meter

I am going to break it down into very simple terms. If I can wrap my mind around the basic physics of a thing, I can understand that thing.

When we are setting up and metering lighting, what are we trying to do? Measure the light falling on the SUBJECT.

Therefore, the light meter should be placed in the same position as your subject, with the light sphere/dome aimed towards your CAMERA position. Check out the lighting diagram in my High Key Lighting Tutorial.

Why? Because you want to light the SUBJECT and you want the subject to look best through the lens of the CAMERA.

But HOW Do You Meter From the Position of the Subject?

Well, you could wait until the subject shows up and ask them to sit/stand/lay where ever it is you intend to photograph them. Then you could ask them to hold the light meter very near their face, aimed towards the camera.

However, if you’re not very experienced yet, that method could be a little nerve wracking. Or maybe your subject doesn’t have opposable thumbs. What then?

I like to set my studio up for a shoot the night before. I use a very tall bar stool with a big box stacked on top, high enough to approximate the height of my subject. I lay my light meter on top of the box, with the sphere aimed at my camera, then I fire my lights and take meter readings.

Start With Your Key Light.

The key light is the main light you will use to illuminate your subject. I like to shoot most things in the studio at f/11 and 125th of a second with an ISO of 200. Therefore I know I want the light output falling onto my subject to equal f/11 at 125th of a second when my camera (and light meter) are set to an ISO of 200.

So fire your light and see what the light meter says. Adjust your strobe head aka light accordingly.

What If I’m Using a Key Light AND a Fill Light?

You want the light output of both to equal f/11 at 125th of a second with an ISO of 200. So fire BOTH lights at the same time and check the readout on your light meter (which is still aimed at the camera.)

If you want your subject lit evenly across (kinda boring, but you’re the boss), then set both lights to the same output, keep firing, checking your light meter and adjusting until you have reached your desired setting.

If you want a little bit of shading on your subject, you’ll want to have the key light set for higher output than the fill light. I usually set my key light at f/8 and my fill light at f/5.6 and this gives me a combined reading of f/11. You can shift that ratio even further for Rembrandt Lighting by setting your key light 2 stops higher than your fill light.

Rembrandt - The Master of....Rembrandt Lighting

What About the Background Light/s?

Decide what type of lighting you would like to use – high key, low key, medium key – aim your lights at your background, place your light meter as close to the center of the background as possible (aimed at the CAMERA) and fire away.

Check your meter reading and adjust accordingly:

High key, you’ll want to set your background lights AT LEAST one stop OVER your subject lighting. For example, that means if your subject lighting is set to f/11, your background lights are set to f/16.
Low key you can just play around and see what looks best to you.
Medium key will closely match the background lighting to the subject lighting.

The Last Thing to Do.

Once you have all of your individual lights calibrated, then place your light meter back in the subject position, dome aimed at the camera position and fire ALL of them at the same time.

The meter should still say you’ve got a setting of f/11 at 125th of a second with ISO 200. If not, something is not set right and you’ll have to start over with the metering and do it in a step-by-step, logical progression.

Orange Skin Tones a Mystery to Me…

Without knowing what type of lighting Sharon is using, I really can’t speak to this issue. It is probably either the type of lighting, or the white balance setting on the camera, or a combination of those two things. It could also be an exposure setting issue.