Posted: Tue May 16, 2006 2:02 pm Post subject: Confusing Photography Terms
I thought it might be good to have a glossery of common photography terms and what they mean....
Contrast: The contrast is the degree of difference between the dark and the light areas of a scene or photograph. High contrast photographs are a result of high contrast lighting, where there are sharp differences in the dark and light, and less in between. High contrast lighting can be achieved with both direct and bounced light that is not softened or diffused, but often reflected from a bright silver surface.
Depth of Field or (DOF): The depth of field refers to the nearest and farthest points in your photograph that are in focus in your shot. A lens can only focus on one single distance fully, but with a wide depth of field, areas both closer and further from that one point are relatively in focus as well. Stopping down to a smaller aperture increases the depth of field, and will result in more of the photograph being in focus.
Lens Flare/Light Spill: With ambient and studio lighting, when light is directed or refracted into the camera's lens, this light is known as lens flare. Some photographers will allow light to be reflected in their camera's lens for an intended glowing effect, but normally light spill is undesired. When using studio lighting to illuminate your subject, you can eliminate light spill by positioning your flash unit and accessories to not direct light back into your camera.
Shutter Speed: Shutter speed is a term which refers to the length of time your camera’s shutter is open. As the shutter opens and closes to expose your film, the shutter speed measures in seconds the length that light is reaching your film. Obviously, the longer the shutter speed, the more light you are letting in. Very fast shutter speeds will allow you to stop action, but require a great deal of light.
Color or White Balance: Refers to the relative intensity of colors in your image. Without correction, a picture taken at sunset can seem too yellow or orange and a picture taken under fluorescent lights might seem too green. Some cameras come with built in automatic white balance correction. You can also adjust the color balance in an image editing software. The colors are divided into three pairs: Cyan and Red; Magenta and Green; and Yellow and Blue. As you increase the amount of one color, you also automatically reduce its inverse.
Compression: Storing image data in a way that results in a reduction in file size. Compressing data is especially important when you want to publish images to the web or e-mail. GIFs, JPEGs, and PNGs are all common compressed file formats. Compression can be lossy or lossless. Lossless compression doesn't lose any image data. GIFs and PNGs are lossless file formats (although GIFs lose color depth). Lossy compression results in the loss of image data every time the image is saved. JPEG is a lossy file format.
HSB: A color model that describes color in terms of Hue, Saturation, and Brightness.
HSL: A color model that describes color in terms of Hue, Saturation, and Lightness.
HSV: A color model that describes color in terms of Hue, Saturation, and Value.
Hue: The distinct characteristics of color that distinguishes blue from red and yellow from green, etc. Technically, hue is the dominant wavelength in the reflected or emitted light.
Interpolation: An algorithm used to create pixels based on existing pixel data when you scale an image.
ISO (ASA) speed: A measure of a film's sensitivity to light. A 400 speed film is more sensitive to light than a 100 speed film. Consequently, the faster film is better suited for low-light photography. Unfortunately, faster films also create more noise and reproduce colors less accurately than slower films. Digital cameras either have a preset ISO sensitivity or they allow you to choose from a variety of film speed settings.
JPEG: Stands for Joint Photographic Experts Group. Along with GIFs, the JPEG file format is one of the main graphic formats displayed on the web. JPEGs use a compression method that sacrifices image information to reduce the file size called lossy compression. This means that every time you save an image as a JPEG, some of the original image data will be lost. JPEGs store images in 24-bit color (GIFs only use 8 bits or less) allowing you to save millions of colors. Consequently, JPEGs are better suited for photographs and images with fine gradations of tone and color.
LCH: A color model that describes color in terms of Luminance, Chroma, and Hue.
Luminance: The lightness or luminance of a color is similar to its value or brightness but the two are not the same thing. In the physical world, luminance is the physically quantifiable intensity of light measured in energy per unit area. On your computer the sun may appear brighter than a tree, but in reality each pixel on the screen is emitting the same amount of energy. Luminance is a way to recreate that light effect on the computer. Colors wash out as luminance increases and colors darken as luminance decreases.
Macro: A one to one or higher magnification of a subject captured on film.
Noise: An unwanted grain pattern in an image often caused by slow shutter speeds and high ISO settings.
Saturation: The intensity of a color with respect to its brightness or value. Given a level of brightness, saturation measures the amount of gray in a color. A color that lacks gray impurities will seem more intense and vivid. Saturation is closely related to chroma.
Sepia: A brownish colored, old-fashioned look to an image often created as a special effect either within a digital camera or in an image editing software.
Composition: The pleasing arrangement of the elements within a scene-the main subject, the foreground and background, and supporting subjects.
I am gonna print this and hang it next to the puter so I can go uhhm whats that mean...OHHHH ok..lol _________________ Canon Rebel XT
Nikon 8700
Nikon 4100
If a Picture is Worth a Thousand Words
I will be Talking for Centuries...
Posted: Tue May 23, 2006 7:15 pm Post subject: Chroma
chro·ma
n.
The aspect of color in the Munsell color
system by which a sample appears to differ
from a gray of the same lightness or brightness
and that corresponds to saturation of the perceived color.
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