A light source used to provide illumination that is focused onto the specimen by the condenser lens.

collects light from the light source and focuses it on the plane of the condenser diaphragm.

modifies the light within the light path between lenses, usually by passing some colors while blocking or attenuating other colors.

comes after the objective lens and before the image plane or the eyepiece, serving to change the size of the image or to provide image-space telecentricity.

gathers and focuses light from the illuminator onto the specimen being viewed.

gathers light from the specimen, which is focused to produce a real image. The objective lens works with the eyepiece lens to magnify the image of the specimen.

folds the light path so that objective lens and eyepiece are aligned. In a stereomicroscope, the beamsplitter divides the light from the objective lens into the two eyepieces.

the lens at the top that the user looks through. The eyepiece lens works with the objective lens to magnify the image of the specimen. The eyepiece lens focuses the real image at infinity so the user can observe with a relaxed eye.