Numerical aperture¶
The Numerical Aperture (NA) describes the amount of light coming from the focus that the objective can collect.
The NA depends on the half angle of the maximum cone of light that can enter or exit the lens. It is directly linked to the resolution of the objective.
Tipically, you can find the NA engraved on the objective next to the magnification.
Note
Notice that depending on the file format that you are using the parameter may be skipped or must be provided.