In imaging optics, a field lens is a positive-powered lens or group of lenses that comes after the

objective lens In optical engineering, an objective is an optical element that gathers light from an object being observed and focuses the light rays from it to produce a real image of the object. Objectives can be a single lens or mirror, or combinations of ...

and before the

image plane In 3D computer graphics, the image plane is that plane in the world which is identified with the plane of the display monitor used to view the image that is being rendered. It is also referred to as screen space. If one makes the analogy of taki ...

or the

eyepiece An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as Optical telescope, telescopes and microscopes. It is named because it is usually the lens that is closest to the eye when someone looks thro ...

, serving to change the size of the image or to provide image-space telecentricity. It is used for the reduction of detector size and, in instances needing high optical gain factor, it can correct aberrations through its several elements. Optical systems that feature multiple image planes are at risk of a potential problem, which involves the inability on the part of succeeding relay lenses to capture a cone of light from the primary objective lens. The field lens - by behaving as a variably angled lens - solves this problem by bending or refracting the cone of light back into the succeeding relay lens. In

X-Ray microscopy An X-ray microscope uses electromagnetic radiation in the X-ray band to produce magnified images of objects. Since X-rays penetrate most objects, there is no need to specially prepare them for X-ray microscopy observations. Unlike visible light, ...

, the field lens is used to produce parallel and homogeneous illumination of the

stencil Stencilling produces an image or pattern on a surface by applying pigment to a surface through an intermediate object, with designed holes in the intermediate object. The holes allow the pigment to reach only some parts of the surface creatin ...

References

{{optics-stub Lenses Microscope components