equivalent focal length
- optics the ratio of the size of an image of a small distant object near the optical axis to the angular distance of the object in radians
Show More
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012