To: atm{at}shore.net
From: Andy Saulietis 
Reply-To: Andy Saulietis 


To clarify:


>BFL = Back focal length

This is the distance to the focal plane from some arbitrary mechanical
location on the lens or imaging system, or it's support structure, etc. For
camera lenses,
usually the distance from the lens mounting flange to the focal plane.
Don't use this distance to calculate magnification, f#, etc because it has
nothing to do with the focal length of the optical system.


Andy Saulietis
ISS Enterprises
PO Box 19
Mayhill NM 88339


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http://www.pvtnetworks.net/~iss/starend1.htm
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