Why use flash?
I was asked recently by a relatively-new amateur photographer, “Why use flash?”
He was mainly shooting photos in locations where there was plenty of ambient light available to make a proper exposure with his camera, and I suspect that the unspoken subtext to his question was that he was wondering if there was any particular reason for him to spend the money to buy an external flash for his camera (or even to use the built-in “pop-up” flash).
Here’s what I told him:
There are two main reasons for people to use flash when making photographs:
- There’s not enough ambient light to make a photograph without flash, or
- The ambient light that’s there is not to your liking, and you want to modify or replace it with “good” light of your own.
Most beginners only think of reason #1. (It’s dark, so I use flash.) Simply adding more light quantity, without giving consideration to its qualities (such as its hardness, color, direction, and relative brightness), typically results in the dreaded “person in a dark cave” portrait.
A more experienced photographer will use flash to supply the light that he wants, where and how he wants it, either alone, or in addition to the existing ambient light.
Personally, I use flash most often when I’m shooting outdoors, in full sun, which is a situation where most amateurs wouldn’t even consider using flash at all.
In full sun, you have plenty of light, but it’s almost always very hard (the sun may be huge, but it’s 93 million miles away, and casts very hard-edged shadows). Also, full sunlight rarely comes from a flattering direction; it’s almost always overhead, which gives people raccoon eyes, and hides their faces in shadow if they’re wearing a hat. Also, full sunlight gives your images more contrast than any camera can capture in a single frame.
Adding flash from my camera position allows me to fill in those shadows without erasing them completely. This way, I can reduce the contrast in the scene to the point where my camera can actually record detail in the shadow areas, and I can avoid raccoon eyes and see people’s faces up under their hat brims. The flash also adds a bit of “sparkle” to the eyes, in the form of a “catch light” reflection.
Outdoors, I’m not generally looking to overpower the sun with my flash. I usually prefer to use flash that doesn’t call attention to itself. Instead of making the scene look “artificially lit”, I simply tame the shadows, and bring them under control.
It all boils down to control. Using flash, you’re able to take control of the lighting in your images, and are no longer at the mercy of the ambient light. To a photographer, that’s a very good thing.
