Long focal length of lens
variable focal length lens
focal length of a theromal lens
focal length of concave lens
focal length of thermal lens
graded focal length lens
short focal length lens
short focal length lens (=short-focus lens)
telephoto lens focal length
Thermal Lens Focal Length
chromatic difference of focal length
Conversion of length of schooling
estimation of focal length
Estimation of length of death
focal length of objective glass
long-period variation of length-of-day
span length of length bar