On-Axis Fill Flash

Max w/- On-Axis Fill

Nikon D300, 70-200mm f/2.8, SB-80DX camera right and high on 1/2 power, second SB-80DX through beauty dish on-axis at 1/16 power, third SB-80DX camera left and behind as rim light.

This week we’ll be taking a look at a little lighting technique for opening up harsh shadows in portraiture. Directional light (like off camera flash) is almost always more visually interesting but can often create a problem of very dark areas on your subject’s face. This may be desirable in some situations but usually you will want to bring some detail back into those areas.

To understand what on-axis fill flash is, let’s break the term down. On-axis refers to the lens axis in relation to your subject. The pop up flash on your camera is an excellent example of a flash that is on the same axis as your camera lens. You’ve no doubt noticed that if you use an on-axis flash like your pop-up as your primary light source you are left with a photograph that often appears flat and is prone to red eye. But an on-axis flash used to simply inform a little more detail into your subject can work wonders. Here’s how:

This technique assumes a few things from get go: you are comfortable with your camera and shooting with flash off camera. You will need 2 camera flashes for this technique to work properly, however your camera’s pop up can act as this second light source.

For the shot in this article I used my D300 with a 70-200mm f/2.8 lens, and 2 old Nikon SB-80DX flashes. My old flashes only operate in manual power setting modes, but you could accomplish this same look with fancier flashes and Nikon’s Creative Lighting System, or Canon’s infrared flash triggering system.

The first light went on a Manfrotto light stand with a 43 inch Westcott shoot-thru umbrella. I placed the light slightly camera right of the subject and above him, so the light came down from above which can cause harse shadows in the eye sockets of your subject.  This is where on-axis fill can step in and save your day. My second SB-80DX was placed on another light stand and fired through my homemade beauty dish (learn how to make your own here: http://tinyurl.com/65mz3a). The flash-beauty dish combo was positioned immediately below my lens.

The real key with this on-axis fill stuff is to mind your power ratios. Whether you set your flash powers manually or with some fancy remote system its important not to overdo it. The umbrella-ed light from up high is our primary light (read: key light) and we want it to stay that way. So with our key light at a 1/2 power setting we dial in a power on the fill light that is several stops under our key. If memory serves the on-axis fill for this shot was on 1/16 power; just enough to bring some detail into the shadows of his face and especially to bring a little light into his eyes.

If you find yourself minus a second speedlight you can replace it with your camera’s built-in flash, simply bring the power level down to keep from competing with your key light. You could also use a ringflash unit to get some truly on-axis fill, however these units tend to be expensive.

The observant among you will notice that this shot has one additional light source. Once I had my two light key/fill combo working well I placed a third SB-80DX on the book shelf behind and camera left of my subject. On minimum power the third light placed a nice little separation light on the left side of Max’s face completing the shot.

Hope you’ve enjoyed this little look into flash photography, hit the comments with questions and if you decide to try this technique out be sure to add your shots to the Pixels Photo Pool on Flickr.

One Response to “On-Axis Fill Flash”

  1. Sam says:

    Nicely written article Ben. Thanks!