HOME

TheInfoList



OR:

Optical format is a hypothetical measurement approximately 50% larger than the true diagonal size of a
solid-state Solid state, or solid matter, is one of the four fundamental states of matter. Solid state may also refer to: Electronics * Solid-state electronics, circuits built of solid materials * Solid state ionics, study of ionic conductors and their us ...
photo sensor. The use of the optical format means that a lens used with a particular size sensor will have approximately the same angle of view as if it were to be used with an equivalent-sized
video camera tube Video camera tubes were devices based on the cathode ray tube that were used in television cameras to capture television images, prior to the introduction of charge-coupled device (CCD) image sensors in the 1980s. Several different types of tub ...
(an "old-fashioned" TV camera). In a video camera tube the diagonal of the actual light-sensitive target was about two-thirds the outside diameter, which was the measure used. The optical format is approximately the diagonal length of the sensor multiplied by 3/2. The result is expressed in inches and is usually (but not always) rounded to a convenient fraction. For instance, a 6.4x4.8mm sensor has a diagonal of 8.0mm and therefore an optical format of 8.0*3/2 = 12mm, which is expressed as inch in
imperial units The imperial system of units, imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed thro ...
. The reason it is expressed in inches is historical, dating back to the early days of television. http://www.dpreview.com/news/2002/10/7/sensorsizes (table of sensor sizes at bottom) Many image device sheets do not list the actual optical format, but do list the size of their pixels in terms of micrometers; a helpful equation can be used to convert the pixel size and array size directly to optical format. The equation for this is: : OF = \frac with: * w = width of array (in pixels) * h = height of array (in pixels) * p = pixel size (micrometers)


See also

*
Image sensor format In digital photography, the image sensor format is the shape and size of the image sensor. The image sensor format of a digital camera determines the angle of view of a particular lens when used with a particular sensor. Because the image se ...


References

Image sensors {{optics-stub