Some wavelengths of light, invisible to the human eye, can be seen and photographed by special cameras and image sensors. Infrared, ultraviolet, and x-rays are among the best known. Infrared photos can create unusual colors; green foliage becomes magenta, and pale skin tones become green. False color images often reveal details that we don’t normally see. Infrared film was originally made to detect hidden military bases, showing the difference between living foliage and dead branches cut for camouflage. It is also used by forensic scientists to spot forgeries in documents and paintings. Some imaging techniques don’t use light at all. A magnetic resonance imaging (MRI) scanner uses a combination of magnetism and radio waves to pick up signals from the human body and then a computer uses these signals to create a visible image. For digital cameras, this can be done though editing software using software filters.
More about Metering Systems
There are four types of metering systems that are commonly found on modern cameras.
- Average metering—Takes light readings from across the whole image and finds the average.
- Center-weighted average metering—Light readings are determined by the brightness in the center of the frame.
- Spot metering—Like a hand-held meter, a spot meter takes readings from a tiny area within the frame. A photographer can point to different areas within the frame to get several readings before choosing a setting.
- Matrix metering—A multi-zone system where the camera compares brightness levels in the zones to determine the best setting.
A hand-held meter has the advantage of taking incident light readings (light falling on the subject), as well as the reflected light reading (light reflected from the scene). A camera’s built-in meter just takes reflected light readings.
The histogram is a graphic chart found on your digital camera that shows the brightness levels of an image ranging from pure black on the left to pure white on the right. If your digital camera offers a histogram, you can use the chart to read the exposure of a photo.
White Balance Settings
The process of compensating for color tone in different light is referred to as balancing the light or white balance. The most common white balance settings are:
- Daylight—for direct sunlight
- Cloudy—for shady, overcast skies
- Fluorescent—for use under fluorescent lighting
- Incandescent/tungsten—for use under standard light bulbs and some types of fluorescent lighting
Some digital cameras have a custom white balance setting. You take a reading off a white colored object to set the white balance. Check your manual for specific instructions. These settings act much like filters adding necessary warm or cool casts to the picture to help accommodate for different lighting situations. If you are using JPEG or TIFF format, setting the white balance is very important. Only the raw format lets you easily adjust white balance when importing the image into your software.
Double Exposure - Moving the Moon
Moving the Moon — You can move the moon so it is right where you want it to be by double-exposing the picture. To do this you need a camera that lets you take one picture on top of another. Check your camera instructions to see if your camera can make a second exposure. Take one night picture without the moon; remember where the dark sky is positioned. Then take a second picture looking up in the sky showing only the moon so that it shows up in the dark sky of your first picture. Try double-exposing night-lights and signs or put your friends on a television screen using a double-exposure.
Black Light — a still life using beads, clear glass goblets, glow-in-the-dark objects, a flashlight covered with colored cellophane, or other objects that represent your Presentation Portfolio theme. Place a black light bulb in a clamp reflector. Set the camera on a tripod and use a cable release. Before taking the picture, focus the camera in a lighted room. Turn out the lights. Depress the cable to open the shutter for 30 or 40 seconds. Then depress the cable to close the shutter.
Three-Headed Person — Set your camera on a tripod in the dark. Cover your subject with black fabric leaving the head uncovered. Prepare three hand-held flashes. Open the shutter. The first flash captures the head facing left. The second flash photographs the head of the person facing the camera. The third flash captures the head facing right. Close the shutter.
Ghost Photography / Apparition
Try some ghost photography. An apparition effect can be created with a camera that has a bulb setting or flash attachment, a tripod, and a cable release or remote.
- Use a hidden light or waning, natural light or create an eerie setting with artificial light.
- Arrange the subject and props to set the mood, for example, a window, a piano, and a person dressed in costume.
- Set the camera on bulb, focus on the subject and part of the window, open the shutter and count to five or less (depends on the light coming in). Then tell the subject to move out of the area, count again, and close the shutter.
- More than one photo shoot might be needed to get the proper apparition effect. Give this photo a title.
Noise pollution or digital noise is generally an unwanted characteristic of a digital photo. Digital noise gives a photo a grainy effect. Digital noise is related to your ISO settings. You generally get the best picture quality by using a low ISO setting. You should only increase the ISO settings when you need a faster shutter speed to avoid a blurry picture. Higher ISO settings produce more noise, which becomes even more noticeable when you enlarge an image. For more information on ISO settings, refer to Book 2, page 17.