Metering Your Studio Monolights Without a Flash MeterNormally, to get the most out of studio monolights, a photographer needs a flash meter to measure the output of the flash so as to set the monolight power and camera exposure settings. With a flash meter, it’s easy to balance a few monolights to ensure that they are producing the desired lighting effects like rim lighting, hair lighting, etc.
However, flash meters can be pricey, even the least expensive Polaris flash meter is list priced at $299.95, although it sells for about $170 in camera stores.
However, with the advent of digital SLRs with built-in histogram analysis of images and color LCD screens, it’s now possible to meter your studio monolights with just the camera alone. It’s something of a process of trial and error, but even an amateur with no experience can do this.
What’s needed to properly meter without a flash meter? Here’s what you need:
1) your monolights
2) your digital SLR
3) someone or something to serve as a model. If no one is available, even a neutrally colored stuffed animal will work.
First, set up your monolights to the lighting configuration you desire. Then turn off all the monolights except the “main” light. Set the main monolight to a setting between ½ and ¼ power. Make sure there are no other sources of extraneous light like an unshaded window or recessed incandescent light.
Plug your monolight into the PC sync connector of your camera. Switch your camera to manual mode “M”. Set your camera’s shutter speed to the correct flash sync speed; typically 1/125 works on virtually all modern SLRs. Next, select the aperture you desire; f/8 is typically a good starting point if you’re unsure where you should start. Set your ISO to the lowest setting on your camera; usually this is ISO 100 or possibly ISO 200. Your white balance should be set to daylight or flash.
Now, you’re ready to take a photo—focus on the eyes of your model or stuffed animal and release the shutter. If all goes well, your studio light should go off. Check your image on the back of the LCD, along with the histogram. If the image appears either underexposed or overexposed, you then need to decide what adjustment you’re going to make.
Let’s say that the image is overexposed. You have two options—either power down the light a little bit or increase your f-stop. Take another photo and check your LCD and histogram. Adjust your light or aperture until you’re satisfied.
Let’s say that the image is underexposed; you need to get more light to the sensor. So, either power up the light or decrease your f-stop to let more light. Take another photo, check the image, and adjust your light power or aperture until you’re satisfied.
Now that you’ve got your main light set up, it’s time to set up your other lights. Turn the next light on and make sure the slave sensor is activated on the light. Aim it where you want. If you want it to have it accent a feature or serve as rim lighting, you’ll want it brighter than your main light. So set the power a little bit more than the main light. Take a photo (both lights should go off) and this time only adjust the power up or down on the auxiliary light after checking the photo. Don’t touch your aperture, shutter speed, or main light power because those features are already set properly.
Repeat this procedure with any other lights you might have. When you’ve finished with the last light—you’re done and ready to start shooting.
Don’t forget to erase your calibration shots when you’re done, so you’ll have plenty of room on the card.