An apparatus for a low numerical aperture exclusion imaging apparatus is provided. The apparatus may include an electromagnetic illumination source for illuminating a portion of a specimen; and for collecting an image created by the electromagnetic radiation an objective lens optically coupled to the electromagnetic illuminated portion of the specimen. The apparatus also includes an optical blocking plate disposed between the objective lens and a focusing lens. The optical blocking plate is positioned to substantially block undesired electromagnetic radiation from image sources distally aligned in the same optical axis as the specimen. This invention enhances narrow depth of field characteristics in imaging and also enhances discreet imaging in a narrow focus field by eliminating some or most of the light which contributes to wide depth of field focus which is useful for optical sectioning ranging from microscopy to photography. Optical sectioning provides the information necessary for 3D image reconstructions and other X Axis spatial measurements.