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Petzval portrait lens. The Petzval objective, or Petzval lens, is the first photographic portrait objective lens (with a 160 mm focal length) in the history of photography. [1] It was developed by the Slovak mathematics professor Joseph Petzval in 1840 in Vienna, [2] with technical advice provided by Peter Wilhelm Friedrich von Voigtländer [de].
The magnification of the eyepiece depends upon its focal length and is calculated by the same equation as that of a magnifying glass (above). Note that both astronomical telescopes as well as simple microscopes produce an inverted image, thus the equation for the magnification of a telescope or microscope is often given with a minus sign .
Distortion (optics) Not to be confused with spherical aberration, a loss of image sharpness that can result from spherical lens surfaces. In geometric optics, distortion is a deviation from rectilinear projection; a projection in which straight lines in a scene remain straight in an image. It is a form of optical aberration.
Chromatic aberration. Focal length of lens varies with the color of light. In optics, chromatic aberration (CA), also called chromatic distortion, color aberration, color fringing, or purple fringing, is a failure of a lens to focus all colors to the same point. [1][2] It is caused by dispersion: the refractive index of the lens elements varies ...
The lens design can be changed even more: in colour apodization the lens is modified such that each colour channel has a different lens aperture. For example, the red channel may be f /2.4, green may be f /2.4, whilst the blue channel may be f /5.6. Therefore, the blue channel will have a greater depth of field than the other colours.
Perspective distortion. Simulation showing how adjusting the angle of view of a camera, while varying the camera's distance and keeping the object in frame, results in vastly differing images. At narrow angles and long distances, light rays are nearly parallel, resulting in a "flattened" image. At wide angles and short distances, objects appear ...
This magnification formula provides two easy ways to distinguish converging (f > 0) and diverging (f < 0) lenses: For an object very close to the lens (0 < S 1 < | f |), a converging lens would form a magnified (bigger) virtual image, whereas a diverging lens would form a demagnified (smaller) image; For an object very far from the lens (S 1 ...
Visulization of flux through differential area and solid angle. As always ^ is the unit normal to the incident surface A, = ^, and ^ is a unit vector in the direction of incident flux on the area element, θ is the angle between them.