Ukukhanya okukhanyayo
Ukukhanya okukhutshwa ngumthombo wokukhanya ngexesha leyunithi kubizwa ngokuba yi-luminous flux yomthombo wokukhanya φ Ukumela, igama leyunithi: lm (lumens).
amandla okukhanya
Ukukhanya okuguquguqukayo okukhutshwa ngumthombo wokukhanya kwiyunithi eqinileyo ye-engile yecala elinikiweyo lichazwa njengokukhanya komthombo wokukhanya kwelo cala, elichazwe njenge-I.
I=I-engile ekhanyayo kwi-engile ethile Ф ÷ I-engile ethile Ω (cd/㎡)
ukuqaqamba
Ukukhanya okukhanyayo kwiyunithi yendawo nganye kwiyunithi eqinileyo ye-engile yesikhanyiso kwicala elithile.Imelwe ngu L. L=I/S (cd/m2), i-candela/m2, ekwabizwa ngokuba yi-grayscale.
isikhanyiso
Ukukhanya okuguquguqukayo okufunyenweyo kwiyunithi yendawo nganye, echazwe kwi-E. Lux (Lx)
E=d Ф/ dS(Lm/m2)
E=I/R2 (R=umgama ukusuka kumthombo wokukhanya ukuya kwinqwelo-moya ekhanyisiweyo)