What is a Fill Light? And How Can I Use It?

A combination of flattering lighting and a compelling subject is what makes a portrait great. There are two main types of lighting you can use after choosing your subject: a main light or a fill lamp.

What is a fill light?

The main light’s purpose is to provide basic illumination for the subject. It could be a speedlite, LED, speedlite or strobe. The fill light(s), however, is intended to fill in a shadow or shadows.

Do not make it appear that you are creating shadows with fill light. This is a key way to use fill light effectively and beautifully. Fill light’s purpose is to illuminate those parts of the subject that main light can’t reach.

Here are some photos I love from Venice’s Carnival. They show you how you can create natural-looking fill lights. First, we’ll use a hand-held LED lamp to fill the light. Next, we will move on to using speedlights.

Compare the images that are featured in this article. The left photograph shows the model, who was standing in the shade, being illuminated only by natural light. This photograph may appeal to those who like mystery and photos that are ambiguous. If you consider the eyes to be a crucial element of portraiture, the fill light photo on the right will probably appeal more to you.

LED (Constant), Light

Below is a behind the scenes shot of me shining a portable LED lamp onto the subject.

Here’s how I got a natural-looking photo.

  1. For a natural-light photo, set your camera to Aperture Priority.
  2. I adjusted the light output of the LED light by moving it closer or further from the subject. I also experimented with increasing or decreasing the output of the LED light.
  3. The warming panel, which is usually a led light, can be used to “warm up” the portrait. You can also warm up the portrait using Lightroom or Photoshop.

The fill light created soft shadows on the wall behind the model in the photograph to the left. This problem can be solved using the same LED technique as above. The model should be moved away from the wall. This is how I took the photo of the model to the right.

Outdoor Speedlight and Fill Light

Compare the images above. The left photograph is taken using only natural lighting. The right photograph uses a speedlight as a fill-light: you will notice that there are no shadows around the subjects. This is because the speed light’s light balances with natural light, which is again the goal of fill lighting in most cases.

First, be aware that this is just one method to achieve the desired effect. It allows me to be completely creative with the light.

Below is the technique:

  1. Your camera should be set to Manual exposure.
  2. The shutter speed can be set to either the maximum flash synch speed or lower.
  3. You should adjust the aperture to get a good exposure of what is the brightest area of the scene (in this instance, the sky).
  4. You can increase your ISO to shoot sharper shots if your shutter speed is too slow (due camera movement or subject movement).
  5. Take a picture with your speed light on TLL.
  6. Reduce the speed light’s output if the subject is too exposed. Increase the speed light output if the subject(s), are too dark.

This technique is particularly useful when the subject is in shade or the background is much brighter than the subject. As illustrated in the photos above.

Another creative idea is to make the background darker than your subject. This will allow the subject to stand out more and gives the photograph a darker mood.

Here’s how to make the background darker.

  1. Your camera should be set to Manual exposure.
  2. The shutter speed can be set to either the maximum flash synch speed or lower.
  3. You can adjust the aperture to make your background underexposed, maybe by one stop or more.
  4. You can increase your ISO to get sharp shots.
  5. Take a picture with your speed light on TLL.
  6. Reduce the speed light’s output if the subject is too exposed. Increase the speed light’s output if the subject is too dark.

Indoor Speed Light and Fill Light

Let’s go indoors to see how a speed light indoors can be used for fill lighting. Both cases are using my Canon 600Ex Speedlite with a Westcott Softbox.

A speed light is a much better choice than an LED light, as a side note. You can therefore photograph closer to your subject and a speed light can be used to take better photos.

Photo by Rick Sammon

The above comparison of fill light and no fill light is shown. Again, I used my speedlight technique for lighting the subject’s eyes.

Note: Speed lights can have other effects on photographs. Even if it’s not in a softbox, speed lights add contrast and sharpness.

My favorite Carnival photo is saved for last. This one used only one speed light.

The above photo shows the same scene, except that the speed light has been removed. Due to the high contrast in the scene, the windows are too bright and the subjects are too dark.

This behind-the scenes photo shows my Westcott Apollo Softbox. The Canon ST-E3 wireless transmitter was attached to my hot-shoe, and I used it remotely to fire the speed light in the softbox.

In this case, I set my exposure for windows first and then adjusted my speed light output to match the light source. Similar to my earlier demonstration of subject-in the-shade, this is also possible.

Here’s a creative and innovative way to use a speedlight as a fill lamp outdoors. We’ll be traveling to the Highlands in Papua New Guinea to illustrate this.

This technique is known as “Dragging The Shutter”. It’s a variation on my speed light fill-light technique.

Here’s how it works:

  1. Your camera should be set to Manual exposure.
  2. Slow shutter speed of 1/4 second.
  3. You can adjust the aperture to make your background underexposed, maybe by one stop or more.
  4. This step is skipped.
  5. Take a shot with your speed light on TLL. Move your camera side-to-side, up, down, or both (this is what I did). You will need to play around with the shutter speed and speed of your camera several times before you get the desired effect.
  6. Reduce the speed light’s output if the subject(s), are too exposed. Increase the speed light’s output if the subject(s), are too dark.

This fill light shot of Huli Wigman shows how motion can be added to still images. It was taken with no camera movement.

You now have all the information you need, so have fun exploring natural lighting techniques for your photo portrait sessions.