For flash on location, a speed light or a regular flash head with an attachment can be used. A speed light is a small flash that can be mounted to the top of a camera or on a light stand, connected with a cable. Radio slaves can also be used but the flash settings have to be set to manual. This is more difficult that using a cable as it can be set to ‘through the lens,’ where the camera will measure the amount of light and tell the flash gun what to do. A speed light will give very flat light if mounted on the camera and pointed directly at the subject however, it is adjustable and can be bounced off flat white walls which provides a more sculptural light.
A standard flash head can also be used but a battery pack is then necessary. With the generator, the flash head won’t display the modelling light as it wastes energy. This makes it more difficult to gauge the direction of light.
The best thing to begin with while on location is setting up the camera first by itself and determining viewpoint and framing. It is important to use the space appropriately, for example taking advantage of a view from a window or nice natural light.
Principles of HDR imagery can be adapted when using flash on location as the flash will light the subject but the sky/background may be overexposed. Underexposing the image will give a more interesting background, as will increasing shutter speed. Changing the aperture will control the flash, whereas changing the shutter speed allows more control over ambient light which is important as they can add unwanted colour casts depending on the environment.