Wide angls lens
Wide angls lens
Wide-angle lens, loosely defined, any lens that has a focal length markedly less than the length of the diagonal of the format it is being used with, i.e. giving an angle of view greater than about 60 degrees. The principle of eliminating distortion by making the lens elements symmetrical about the stop was discovered in the 1860s, but early wide-angle lenses showed severe fall-off in image illuminance towards the edges of the format, and various devices were adopted to minimize this. The problem has been largely solved by introducing highly curved negative meniscus elements at the front and rear of the lens so that the peripheral rays pass more nearly perpendicularly through the stop (the Slussarev effect). The introduction of the fisheye lens, with its severe barrel distortion, has made it necessary to distinguish this from the orthoscopic (or ‘rectilinear’) wide-angle lens with correct perspective drawing. Modern designs of the latter can cover up to 120 degrees with zero distortion and little fall-off.
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In photography, angle of view describes the angular extent of a given scene that is imaged by a camera. It parallels, and may be used interchangeably with, the more general visual term field of view
It is important to distinguish the angle of view from the angle of coverage, which describes the angle of projection by the lens onto the focal plane. For most cameras, it may be assumed that the image circle produced by the lens is large enough to cover the film or sensor completely.
Calculating a camera's angle of view
For lenses projecting rectiliner (non-spatially-distorted) images of distant objects, the effective focal lengh and the image format dimensions completely define the angle of view. Calculations for lenses producing non-rectilinear images are much more complex and in the end not very useful in most practical applications.
Angle of view may be measured horizontally (from the left to right edge of the frame), vertically (from the top to bottom of the frame), or diagonally (from one corner of the frame to its opposite corner).
Portraiture With a Wide Angle Lens
What's the difference between
a telephoto and wide angle lens
isn't it like similiar?
Color temperature
Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, and other fields. The color temperature of a light source is determined by comparing its chromaticity with that of an ideal black-body radiator. The temperature (usually measured in kelvin (K)) at which the heated black-body radiator matches the color of the light source is that source's color temperature; for a black body source, it is directly related to Planck's law. Yellow-red colors are considered warm, and blue-green colors are considered cool. Confusingly, higher Kelvin temperatures (3600–5500 K) are considered cool and lower color temperatures (2700–3000 K) are considered warm. Cool light produces higher contrast and is considered better for visual tasks. Warm light is preferred for living spaces because it is considered more flattering to skin tones and clothing. Color temperatures in the 2700–3600 K range is recommended for most general indoor and task lighting.
So what's the practical value of all this information?
Well you would use a telephoto lens to capture images of subjects that you cannot get close enough to so that they do not look too small when you print the picture. Examples of this are the sports images you see in the local newspapers. It looks like the photographer must have been standing 3 feet away from the batter or the quarterback when in fact he was more like fifty to a hundred feet away with a huge lens such as a 600mm or 800mm lens that was 18 inches long and weighed 5 pounds!
The wide angle lens is used to capture a group of people, a mountain vista, a house, etc...
I see that some people are still confusing zoom lens with telephoto lenses. Zoom lenses are lenses that can vary their magnification as well their angle of coverage. There wide angle zoom lens (i.e. 17-35mm) and telephoto zoom lens (i.e. 100-300mm) even zoom lenses that traverse the range from wide angle to telephoto ((i.e. 28-200mm).
Your question is a good one and important to understand to fully enjoy photography as I do. I suggest that, if you have the time, take a photography course at your local college continuing education division or local computer club. You will gain a greater understanding and appreciation for the aspects of photography that will enable you capture your memorable moments with greater quality
Wide-angle lens is the opposite of the telephoto lens. It provides a broader viewing field than the human eye. It can be used to take picture of a wide subject in a tight spot. A telephoto lens compresses space whereas a wide-angle lens deepens space; it makes everything seem further away from the camera. It also deepens depth of fields.
Wide-angle lens is not common with consumer digital cameras due to the tiny size of the image sensor or CCD in digital camera, making it expensive and difficult to manufacture. Wide-angle lens is quite common with 35mm format cameras
Categorizing different lighting
Because it is the standard against which other light sources are compared, the color temperature of the thermal radiation from an ideal black body radiator is defined as equal to its surface temperature in kelvin, or alternatively in mired (micro-reciprocal degrees kelvin).[1] For source other than ideal black bodies, the color temperature of the thermal radiation emitted from it may differ from its actual surface temperature. In an incandescent light bulb the light is of thermal origin and is very close to that of an ideal black-body radiator.
However, many other light sources, such as fluorescent lamps, emit light primarily by processes other than raising the temperature of a body. This means the emitted radiation does not follow the form of a black-body spectrum. These sources are assigned what is known as a correlated color temperature (CCT). CCT is the color temperature of a black body radiator which to human color perception most closely matches the light from the lamp. Because such an approximation is not required for incandescent light, the CCT for an incandescent light is simply its unadjusted temperature, derived from the comparison to a black body radiator
The sun
As the sun crosses the sky, it may appear to be red, orange, yellow or white depending on its position. The changing color of the sun over the course of the day is mainly a result of refraction and, to a lesser extent, scattering of light, and is unrelated to black body radiation. The blue color of the sky is not due to black-body radiation, but rather to Rayleigh scattering of the sunlight from the atmosphere, which tends to scatter blue light more than red. This phenomenon has nothing to do with the properties of a black body.