Fill flash adds a gentle burst of light to the shadowed side of your subject while the sun remains the main light. Expose for the background, then dial the flash down until it just opens up the face without looking added on.
When Fill Flash Helps
Bright midday sun throws dark shadows under eyes, noses and hat brims. Backlit subjects can turn into silhouettes when you expose for the sky. Fill flash handles both without overpowering the scene. It balances the two so detail shows in the face and the background keeps its tone.
Set It Up Step by Step
- Switch the camera to aperture priority or manual mode.
- Set a low ISO such as 100 or 200 and an aperture between f/5.6 and f/8 for a general range.
- Check your flash sync speed in the maker’s guide. Many cameras limit it around 1/200 second.
- Meter for the background and sky so they look natural.
- Turn the flash on and set its output to about minus one to minus two stops from normal.
- Take a frame, check the face, and raise or lower the output in small steps.
Flash Power and Distance
| Scene | Opening flash adjustment | Why |
|---|---|---|
| Open shade, soft light | Minus 2 stops or off | Little fill needed |
| Midday sun, face in shadow | Minus 1 to minus 2 stops | Lifts shadows, stays natural |
| Backlit portrait | Minus 1 stop to normal | Balances bright sky behind |
| Subject close to camera | Lower still | Close flash is strong |
Handle Fast Shutter Limits
If the scene is too bright for your sync speed, you may need a smaller aperture, a lower ISO or a neutral density filter. Some flashes and cameras offer high-speed sync, which lets you use faster shutter speeds at reduced flash power. Check the guide to see whether your gear supports it.
Look at catchlights in the eyes. A small spark is pleasant; a big white flash means it is too strong or too close.
Practice with a friend in the same light before an important shoot. Try the flash at three power levels, compare the frames on a larger screen, and note which one looks most natural. That quick test saves time when the real moment arrives.
FAQ
Should I use the built-in flash for fill?
Yes, it can work well at low power for close portraits. Its fixed direction and small size make it a bit more direct, so keep the output low.
Why does my subject look pasted on?
The flash is likely too strong. Lower the power until the shadow side is only slightly brighter than it would be without flash.
The Short Version
Let the sun set the exposure, then add flash at reduced power to open the shadows. Keep within the sync speed, adjust in small steps, and check the face on the screen. Subtle fill usually looks best.
