T-NUMBER


Meaning of T-NUMBER in English

ˈ ̷ ̷ˌ ̷ ̷ ̷ ̷ noun

Usage: usually capitalized T

Etymology: t otal light transmission + number

: a number that is similar to the f-number but takes into account the amount of light actually transmitted by a lens after loss by absorption and reflection and that equals the f-number divided by the square root of the transmittance

Webster's New International English Dictionary.      Новый международный словарь английского языка Webster.