provides an even cone of light that illuminates the specimen. Light from the condenser converges on the specimen, passes through it, and diverges to from an inverted illumination cone that is captured by the objective lens. The Abbe condenser is the most common. The condenser numerical aperture (NA) should be equal to or greater than the highest objective NA., usually 1.25 to 1.32 for a 100x oil objective. The resolving power of the optical system composed of condenser, objective ocular lens is limited to the lowest NA of its individual components.