Each line on a histogram indicates the number of pixels at color tones from black to white.
Learning flash photography requires practice with various settings and under various conditions. Some photographers may use a built-in flash, and others may use detachable flash units. A thorough approach to learning flash photography involves shooting at controlled subject-to-flash distances under different conditions with various aperture settings. Logging the conditions and settings in a notebook provides a reference and builds a thorough understanding of results to expect from future flash photography shoots.
Instructions
1. Set the flash unit to Front Curtain Sync mode. This mode instantly fires the flash when the front shutter curtain on your camera completely opens, and is sufficient for most flash applications including stop-motion photography.
2. Set the camera to ISO 100 or the lowest ISO that your camera offers.
3. Set the camera to Aperture Priority mode, or Av mode. This is a semi-automatic mode that allows you to control the depth of field in a shot by setting the aperture while the camera automatically sets the shutter speed.
4. Set the aperture to the widest full stop (i.e. smallest f/number) on your camera. Common full stops include f/1, 1.4, 2.8, 4, 5.6, 8, 11, 16 and 22.
5. Jot down the lighting conditions of the environment. Time of day, weather and location information is relevant for outdoor photography. Information about ambient light sources is relevant for indoor photography. Write down the kind, distance and position of existing sources of light relative to the subject.
6. Make a note of the camera's distance from the subject.
7. Aim the flash head directly at the subject and fire off a shot.
8. Record the aperture setting, shutter speed and your general impressions about the shot's appearance by viewing the shot with your camera's Preview and Info functions.
9. Write down the camera's evaluation of the exposure by reviewing the histogram for the shot with the camera's Info function. Each line on the histogram graph represents the number of pixels at a color tone from black (left) to white (right). Overexposed shots lack lines on the left side of the graph and lack image detail in the shadows. Underexposed shots lack lines on the right side of the graph and lack image detail in the highlights.
10. Set the aperture to the next widest full stop (i.e. smallest f/number) on your camera, and repeat steps 4 through 8.
11. Repeat steps 1 through 10 at half the distance from the subject and at twice the distance from the subject, but do not shoot at distances that definitely over or underexpose the shot. If a shot is overexposed, do not shoot closer to the subject unless the camera is set to a narrower aperture (i.e. larger f/number). If a shot is underexposed, do not shoot further from the subject unless the camera is set to a wider aperture (i.e. smaller f/number).
12. Pick the best shots, and refer to those settings when shooting under similar conditions.
13. Repeat steps 1 through 12 as thoroughly as possible under various lighting and subject conditions. Some conditions may include very low light indoors and outdoors, sunlight outdoors at noon, outdoor in shade at noon, movement at night, various activities and sporting events.
