Attaching a flash to one’s camera has been, and still is, a hot topic of discussion that was going on long before I got serious about photography in the 1970’s.
I remember being confused, well actually, really confused, and read everything I could find trying to understand how a flash attached to my camera’s hotshoe worked, and how adding light from a flash (on and off camera) could be used to enhance my photography.
Early flashes produced a constant amount of light no matter how close the subject was, and over or under exposures were common. The most frequent way of controlling flash power was to use exotic technology like a white handkerchief, a translucent soap holder, or attaching a white bounce card to the flash.
Later technological development included light measuring sensors in the flash that read the light reflected back from the subject and shut off the flash when a predetermined amount was reached.
Then TTL (through-the-lens) flash came along and small computers in the camera controlled the flash. The reflected light was read by the camera, making the lens focal length, the aperture, and the distance all part of the exposure equation.
Today’s hotshoe connected flash is nothing short of amazing, and there is absolute control over the flash.
Subtracting light intended for the subject no longer needs some translucent material placed over the flash head.
Using devices like white cups, and bounce cards with a TTL flash have become all about softening or diffusing the light instead of only reducing it.
The latest flashes easily control power output, and can be comfortably used with wireless off-camera technology. Alternatively, the flash can also be connected by a dedicated cord and still remain off-camera allowing the photographer to point the flash toward the subject at flattering angles without time consuming calculations.
A photographer can, while shooting, easily select the exposure in camera, or dial the flash power output up or down. It is now so simple to reduce or increase the ambient exposure while maintaining or brightening the subject alone for more natural looking photographs than it was with early flash photography.
When I began using a flash many years ago it changed the quality of my photography. It became just like the image change I gained by using different focal length lenses.
I no longer had to rely on ambient light and I began to notice my subjects had more “pop” than those without the flash and I was pleased at being able to fill unflattering shadows coming from overhead lighting and reduce deep shadows caused by sunlight.
The modern speedlight (hotshoe) flash gives a photographer control over the quality of light and using a flash (or several flash units off-camera) when photographing people is more than just brightening up subjects in a darkened room.