Tuesday, March 16, 2010

How To Speak Photo-geeze

your word for today is...

ABERRATION (ab-er-ay-shun)

(1) Something that prevents light from being brought into sharp focus, dis-enabling the formation of a clear image.

(2) Lens flaw - the inability of a lens to reproduce an accurate, focused, sharp image. Aberration in simple lenses is sub-categorized into seven types:

  • Astigmatism - lines in some directions are focused less sharply than lines in other directions,
  • Chromatic aberration or Axial chromatic aberration - different wavelengths of light coming into focus in front of and behind the film plane, resulting in points of light exhibiting a rainbow-like halo and reduction in sharpness,
  • Coma - the image of a point source of light cannot be brought into focus, but has instead a comet shape,
  • Curvilinear distortion - distortion consisting of curved lines,
  • Field curvature - the image is incorrectly curved,
  • Lateral chromatic aberration also known as Transverse chromatic aberration - variation in the magnification at the sides of a lens (this aberration type used to be termed “lateral color”),
  • Spherical aberration - variation in focal length of a lens from center to edge due to its spherical shape - generally all parts of the image, including its center
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