Numerical Aperture Light Cones
θ (15.0°)
Specimen
Objective
Front Lens
NA = n sin(θ)
0.25 = 1.0 sin 15.0°
NA = Numerical Aperture
n = Refractive Index
= 1.00 (Air)
θ = 1/2 Angular Aperture
Approximate Magnification: 10x
Numerical Aperture