Presentation on theme: "Mrs. Dornbach. How is a Photograph Captured? Photographs are taken by letting light fall onto a light-sensitive medium, which records the image. In."— Presentation transcript:
How is a Photograph Captured? Photographs are taken by letting light fall onto a light-sensitive medium, which records the image. In traditional film-bearing cameras, this medium is the actual film. In digital cameras, a digital sensor records the image.
Camera Construction Basics… a light-tight box that stores a light-sensitive device (either a film or a digital sensor) a lens that magnifies and focuses the image onto that light-sensitive device through a hole in the box (called the aperture) a shutter that opens and closes when you press the shutter release, exposing the film or sensor to the light (this is why a picture is sometimes called an exposure)
Letting in the Light! The amount of light entering the camera depends on the amount of available light. A bright sunny day has more available light than a cloudy one, which in turn has more light than indoor tungsten lighting. To create an image that looks similar to what our eye sees, the film or sensor must be exposed to the right amount of light. Not enough light and the image will be dark, or underexposed. Too much light and the image will be washed out, or overexposed.
Why Manual Mode Makes Art? Selecting the Program or Auto mode allows you to use automatic features such as light metering, shutter speed and focus. (This usually results in successful exposures.) Selecting the Manual mode allows you to control three basic variables: 1) ISO / ASA 2) Shutter speed 3) Aperture The more control you have over your settings, the more your creativity will control your art!
ISO / ASA / FILM SPEED The measure of photographic film’s sensitivity to light. (Lower ISO film, or slow film requires a longer exposure time. Higher ISO film, or fast film records the same image in a shorter exposure time.) Also known as ISO / ASA / ANSI The International Organization of Standards or ISO, a governing body based in Europe that provides the standards for a wide variety of subjects. In photography the standard refers to ratings of film speed. In the past this was known as ASA or the American Standards Association, which is now discontinued and replaced by the American National Standards Institute or ANSI. Standard film speeds include ASA 50, 100, 200, 400, 800 and 1600. (There are specialist films that would go higher or use infra-red.)
ISO / ASA / FILM SPEED Numbers in the small window on the Shutter Speed dial allow you to select the ISO/ASA/ANSI that corresponds to the film you are using.
SHUTTER SPEED The amount of time your camera’s shutter is held open, which controls the amount of light entering your camera and exposing the light-sensitive device. Shutter speed also shows motion. A slow shutter speed show motion by blurring the image, while a fast shutter speed “freezes” motion.
SHUTTER SPEED Numbers in white are the shutter speeds measured in fractions of a second, the time taken from when the shutter opens to when the shutter closes, after you’ve press the shutter release. Shutter speeds are 1/30th of a second, 1/60th of a second, 1/125th of a second, etc. Moving from one speed to a faster one halves the amount of light entering the camera. While moving to a slower shutter speed, doubles the amount of light entering the camera. The change from one speed to another is called moving a stop.
APERTURE The size of the diaphragm (lens opening) letting light into the camera. Aperture also controls the depth-of-field (the distance between the closest and farthest points in which an image is acceptably sharp). Aperture can be used to create emphasis on one subject by blurring the background (wide aperture = low f/stop) or to focus equally on everything in the image (narrow aperture = high f/stop).
APERTURE Apertures are measured in something called f/stops, found on the aperture ring. A very small aperture is f/19, known as “closed”, where the aperture blades are visible. A very wide aperture is f/2.8, known as “wide open”.
Experiment and Enjoy! Keep a running record of the settings you select on each photograph on your log sheets. This will make it possible for you to achieve a maximum range of effects with minimal frustration !