A beginner’s flash photography tutorial
This flash photography tutorial will cover the basics of the two unique types of camera flash: built-in units which are an integral portion of the camera (found on nearly all compacts, and on most SLRs); and separate units that attach to a special mounting ‘shoe’ on the leading of the camera (generally designed for when additional flash power is required with an SLR camera).
Standard add-on flash A basic flashgun measures the quantity of light reflecting from the subject itself, making use of a smaller ‘eye’ in the front of the unit. The spread and angle of illumination is fixed.
Virtually all modern day flash photography units include a light-sensitive cell that measures the light reflecting back from the scene. This reading is used to automatically manage the duration of the flash exposure. Several cameras with ‘dedicated’ or built-in flash units measure the flash light reflected back from the film itself and cut off the flash light when it is actually properly exposed.
When attached to the hotshoe, dedicated units grow to be an integrated portion of the SLR
camera. They lock into the camera’s circuitry, altering the shutter speed using the flash light reading. Data from the camera about the aperture and film speed is used to determine how much light your flash photography will need.
Red-eye The built-in flash located on many cameras often causes problems, commonly known as ‘red-eye’ – where the pupils of people’s eyes show up bright red. This is caused when the angle between the lens, subject and flash is too narrow. That is to say, the flash is located close to the lens.
With fixed, forward-facing flash this is impossible to correct. Quite a few models make an effort to lower the problem with a particular red-eye mode which utilizes a pre-flash to lessen the size of the person’s irises. With SLRs, a separate gun is often utilized, so the distance between camera and flash may be spread to avoid the problem entirely.
Inverse square law flash photography tutorial
If you double the distance between flash and subject, the lighting will be spread over four times as much area. This relationship is know as the inverse square law because the intensity of the light falling on the subject will fall off as the distance squared.
Another difficulty with forward-facing flash is the fact that it produces stark, usually unattractive, results. Some flash photography units have tilting and/or swivelling heads that permit the flash light to be bounced off the ceiling or nearby wall. Results are softer and more natural-looking.
Be careful using this technique with color photography, since the flash light will take on the color of any surface it is bounced off and generate a color cast in the image. It is also important to note that bouncing diffusing flash lighting will dramatically reduce it’s intensity.
The illuminating power of flash falls off rapidly. Each time you double the distance in between the flash along with the subject, light covers four times the region and, thus, is only one-quarter as powerful. This accounts for the fact that standard flash shots with objects inside the foreground are
correctly exposed even though those farther away appear unlit.
It is always a good idea to buy a flash that is as powerful as you can get. This lets you capture flash photography at greater distances and to take fuller advantage of bounce and diffusing techniques. Flash energy is indicated by its guide quantity (GN) – the greater the GN the more effective its output.
Flash fall-off also happens when the spread of light is not as wide as the angle of view of the lens. This produces a well-exposed central location with progressively darkening edges. You either must change lenses and use one having a narrower angle of view or use a light-diffusing attachment with the flash head. Because this will spread the light from the flash over a wider area, an unavoidable loss of flash intensity will result.
Keeping the lessons from this flash photography tutorial in mind will help your images to turn out better in a wide range of situations.