T-number or T numbern (Photography) photog a function of the f-number of a camera lens that takes into account the amount of light actually transmitted by the lens[from T(otal Light Transmission) Number]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
T number
T number n. one of a series of calibrations of the lens openings of a camera according to the intensity of transmitted light. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.