Lens Aperture. South Pasadena High School Final Exam Study Guide- 1 st Semester Photo ½. Study Guide Topics that will be on the Final Exam

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1 South Pasadena High School Final Exam Study Guide- 1 st Semester Photo ½ Study Guide Topics that will be on the Final Exam The Rule of Thirds Depth of Field Lens and its properties Aperture and F-Stop Shutter Shutter Speed Main Light- The primary source of illumination, casting the dominant shadows. Direct Light- Light shining directly on the subject and producing strong highlights and deep shadows. Diffused Light-Light that has been scattered by reflection or by passing through a translucent material. An even, often shadow less, light. Elements of Art Principles of Design Lens Aperture Though you re not likely to notice it unless you look directly into the lens as you take a picture, there is small iris-shaped diaphragms in the middle of your lens that opens and closes at the instant you take a picture. This diaphragm is known as the lens aperture and it controls the amount of light that reaches your camera s sensor. Aperture settings are defined by a series of numbers-in this case they are called f/numbers (or in photo slang, f/stops). But here s the tricky bit with regard to f/stop numbering: The larger the f/number is, the smaller the opening in the lens. The smaller the f/number is, the larger the opening in the lens. A lens opening of f/16, for example, is relatively tiny when compared to an aperture of f/4. If you have trouble remembering which apertures let in more light and which let in less, think of them as fractions: If one of your friends offers you ¼ of a pie, they re giving you a lot more than if they only offer you 1/16. REMEMBER! HIGH F/NUMBERS= SMALLER LENS OPENING LOW F/NUMBERS= LARGER LENS OPENINGS NOTE: As you move to the next larger lens opening (from f/5.6 to f/4, for example, which is moving one stop up) you double the amount of light entering the camera. Similarly, as you move to the next smaller f/stop (f/11 to f/16), for instance, which is moving one stop down) you cut the amount of light in half.

2 Understanding Exposure Exposures are made when the camera allows light to enter the lens and record on the digital imaging sensor. A certain amount of light is needed to make the proper exposure in any given situation for a certain subject. How the camera gets just the right amount of light is one of the creative aspects of photography. The amount of light can be controlled in three basic ways: 1. APERTURE: This is the size of the opening in the lens, and is expressed in an f/stop such as f/4. The aperture only allows a certain amount of light to strike the imaging sensor. It also affects how much of the scene (from foreground to background) is in sharp focus. If you want to emphasize your subject by placing the background out of focus, select a large f/stop (small f/number) such as f/2.8 of f/4 If you are photographing multiple people who are at different distances from the camera, select a small f/stop (large f/number) such as f/11 or f/ SHUTTER SPEED: This is the length of time the shutter is open. Shutter speed not only allows a certain length of time, it also affects how sharp or blurry the picture is due to camera shake, subject movement, or both. If you are shooting a moving subject, a shutter speed of 1/500 is faster than 1/50, so it has better action-stopping capability. 3. EQUIVALENT ISO: The ISO setting adjusts the camera s response to light. At higher ISO settings, the sensor s output is amplified to be more sensitive to light. However, higher ISOs also degrade the picture quality. SUNNY DAYS: Use auto or low ISO settings such as ISO 50 or ISO 100 CLOUDY DAYS: USE ISO 400 NIGHT TIME: USE higher ISO

3 REMEMBER! Higher ISO produces grainy images. DIM LIGHTING & ACTION: If you are getting blurry picture, switch to a higher ISO setting MORE IN FOCUS: If you want as much in focus from foreground to background as possible, switch to a higher ISO setting or use your landscape mode (if your camera offers it). LESS IN FOCUS: If you want a portrait to have a blurry, less distracting background, switch to lower ISO setting or to Portrait mode. Elements of Art Line: A point moving in space. Line can vary in width, length, curvature, color, or direction. Shape: A two-dimensional area or plane that is closed. It can be organic or geometric. Form: A three-dimensional volume or the illusion of three dimensions (related to shape, which is two-dimensional). Value: Lightness or negative area between, around, above, below or contained within objects. Space: The positive or negative area between, around, above, below or contained within objects. Color: The visual sensation dependent on the reflection or absorption of light from a given surface. The three characteristics of color are hue, value, and intensity. Texture: The surface quality of materials, either actual (tactile) or implied (visual). It is one of the elements of art. Principles of Design Balance: The arrangement of visual art elements are arranged to create a feeling of equilibrium in a work of arts. The three types of balance are symmetry, asymmetry, and radial. Contrast: The difference between two or more elements in a composition.

4 Movement: Used to create the look and feeling of actions and to guide the view s eye throughout the work of art. Repetition: The reoccurrence of elements of arts at regular intervals. Rhythm: Intentional, regular repetition of design elements to achieve a specific repetitious effect or pattern. Unity: The total visual effect of a composition achieved by the careful blending of the elements of art and principals of design. Variety: A principal of art concerned with combining elements of art in different ways to create interest. Vocabulary 1. Digital Camera- A camera that captures the photo not on film, but in an electronic imaging sensor that takes the place of film 2. Depth of Field- Refers to how much of the scene is in focus, both in front of and behind the subject or the point of focus. 3. Digital-imaging Sensor- The light-sensitive silicon-based chip used in digital cameras, scanners, and copiers. 4. Exposure- The amount of light and the duration of time that light is allowed to expose film or a digital-imaging sensor. 5. Focal Length- The focal distance, in millimeters, of a lens when it is focused on infinity. The focal distance is the measurement of the optical center of the lens, where the aperture is, to the sensor plane. 6. F-Stop- A numerical representation of the diameter of a lens aperture. 7. ISO (International Standards Organization) - It is a standardized way to measure the sensor s sensitivity to light. 8. LED (Light-emitting diode)- A display in the viewfinder of some cameras that gives you information about aperture and shutter speed settings or other exposure data. 9. Macro Lens- Special lenses that are designed for extremely close focusing.

5 10. Pixel- Short for picture element, a pixel is the smallest imaging unit in an imaging sensor or a digital image. 11. Resolution- The sharpness and fine detail in an image. In digital cameras, this is measure in pixels per inch (ppi). 12. Shutter- A mechanism, inside either the lesn of the camera body, that opens and closes allowing light to hit the film or digital-imaging sensor. 13. SLR (Single Lens Reflex)- A camera with a hinged mirror that reflects the projected image from the lens into a prism or ground glass. 14. Zoom lens- A lens with variable focal lengths that can continuously change from wider views to closer views.

6 The smaller the aperture the greater the depth of field The size of the aperture affects how much of the image will be sharp, known as the Depth of Field or the distance in a scene between the nearest and farthest points that appear sharp in a photograph The shorter the focal length of the lens, the greater the depth of field.