The shell is involute, lenticular, with a narrow umbilicus and moderately high aperture.

Solid immersion optics (allowing an extremely high numerical aperture).

Configurations with a high numerical aperture can measure on relatively steep flanks.

The fine details, and brighter image, that are normally associated with the high numerical apertures of conventional lenses can be reliably produced.

These objectives have a high numerical aperture which gives a small depth of field.

When people want even more resolution, they use heavier particles such as ions, or maybe use an objective lens with higher numeric aperture.

From this it is clear that a good resolution (small δ) is connected with a high numerical aperture.

In microscopy high numerical apertures are desirable to capture as much light as possible from a small sample.

A high numerical aperture (equivalent to a low f number) gives a very shallow depth of field.

He was looking out from the cella, through the atrium, to the high, thin apertures through which the dawn entered the temple.