Standing in your backyard late in the day, for instance, you might find that the low-angle sunlight provides a nice key light for a portrait subject. With the sun at your back, the light is strong and direct, and it may work perfectly fine. But if you change the position of the subject, say, moving her closer to the wall of your house, you might get a bit of fill light from the reflection. Now you’re fine-tuning your lighting without any extra equipment. I’ve used light-colored walls, white-panel vans—even trees with light leaves can work to bounce soft light in this scenario.
Depending on how the sun is striking the light-colored area you’ve found, you may be able to use it as a key light as you might in studio. Turning the subject and positioning yourself so that the sun is at her back (acting like a hair light) and the light is reflecting off of the white wall, for instance, is strong enough to act as a key. Better still, this reflected key light is now diffused so it’s a softer, more traditionally ideal portrait light. And with the sun itself providing a rim light, you can create a more controlled lighting scenario much as you might in the studio.
Even though you can’t reposition the lights or the reflectors, how you position the subject and the camera makes all the difference in the world.
What if there’s no white-panel van or bright home siding available to provide the perfect reflector? Well, consider positioning the subject out of the direct sunlight and in open shade. Simply eliminating the sunlight from directly illuminating the subject will soften the lighting. You can do this by standing the subject under a tall tree or in any area where shade keeps the sun from hitting them directly. As long as their view is still open to bright sky or, in some cases, the bright reflection of sunlight off the ground in front of them, you’ll make a nice, indirectly illuminated picture. The sky is preferable as the key light in this scenario, as it’s generally better to illuminate subjects from above rather than below. Whatever is providing the illumination—open sky or reflected light from a light blue wall or bright green grass—pay attention to any color shifts that may occur. You just might have to adjust for a bit of green cast from grass when editing the image in post.
Lastly, if you want to make negative fill—i.e., add a stronger shadow—you can do that outdoors, as well. I find that positioning a portrait subject very near a tree—maybe just a couple of feet or even inches away—will have the effect of shaping the light. The tree serves as a flag would in the studio, deepening the shadow and eliminating light from reaching the subject from that side. It’s yet another way to take advantage of what’s already there in order to direct and shape light as you wish.