Formulas and Guidelines
We hope that the information which follows will assist you
Points of Magnification
Magnification at Camera
All cameras have a fixed sensor size. Thus, no matter how
Magnification at Monitor
When the camera image is displayed on a monitor for
Example: A 2/3" camera is being used with a 9" monitor and the 11mm diagonal on the camera is being expanded to 9" (228.6mm) for a magnification of 20.8X.
In reality, because no manufacturer wants to have dark edges on the monitor, the camera is actually overextended in order to overfill the monitor, thereby guaranteeing no dark edges. There is no recognized industry standard, but a 5-10% increase in magnification with a resulting 5-10% loss of field can be assumed. It is in this area that a zoom lens provides freedom to implement the adjustment.
Millimeters Inches Resolution in line pairs (3000 x N.A.)/mm (75,000 x N.A.)/in Depth of field + .0005 + .00002 - - ________ _________ 2 2 N.A. N.A.
1 Inch =25.4 mm 1 Meter =39.37 inches 1 Micron =0.001 mm
Definition of Terms
Depth of Field - The distance over which acceptable image
Depth of Focus - The distance along the optical axis over
Field of View - The area visible through a lens or lens system.
Magnification - A measure of the apparent difference in
Numerical Aperture - A term representative of the largest
Resolution - The ability of a lens system to image closely
Working Distance - The clearance or distance between the
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Revised: February 18, 2010.