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  2. Cardinal point (optics) - Wikipedia

    en.wikipedia.org/wiki/Cardinal_point_(optics)

    The cardinal points were all included in a single diagram as early as 1864 (Donders), with the object in air and the image in a different medium. Cardinal point diagram for an optical system with different media on each side. F for Focal point, P for Principal point, NP for Nodal Point, and efl for effective focal length. The chief ray is shown ...

  3. Optics - Wikipedia

    en.wikipedia.org/wiki/Optics

    A ray tracing diagram for a converging lens ... The wave model can be used to make predictions about how an optical system will behave without requiring an ...

  4. Astigmatism (optical systems) - Wikipedia

    en.wikipedia.org/wiki/Astigmatism_(optical_systems)

    This plane often represents the best compromise image location in a system with astigmatism. The amount of aberration due to astigmatism is proportional to the square of the angle between the rays from the object and the optical axis of the system. With care, an optical system can be designed to reduce or eliminate astigmatism.

  5. Numerical aperture - Wikipedia

    en.wikipedia.org/wiki/Numerical_aperture

    Simple ray diagram showing typical chief and marginal rays. In most areas of optics, and especially in microscopy, the numerical aperture of an optical system such as an objective lens is defined by

  6. Visual system - Wikipedia

    en.wikipedia.org/wiki/Visual_system

    In the visual system, retinal, technically called retinene 1 or "retinaldehyde", is a light-sensitive molecule found in the rods and cones of the retina. Retinal is the fundamental structure involved in the transduction of light into visual signals, i.e. nerve impulses in the ocular system of the central nervous system.

  7. Ray (optics) - Wikipedia

    en.wikipedia.org/wiki/Ray_(optics)

    The principal ray or chief ray (sometimes known as the b ray) in an optical system is the meridional ray that starts at an edge of an object and passes through the center of the aperture stop. [5] [8] [7] The distance between the chief ray (or an extension of it for a virtual image) and the optical axis at an image location defines the size of ...

  8. Human eye - Wikipedia

    en.wikipedia.org/wiki/Human_eye

    The lens shape is changed for near focus (accommodation) and is controlled by the ciliary muscle. Between the two lenses (the cornea and the crystalline lens), there are four optical surfaces which each refract light as it travels along the optical path. One basic model describing the geometry of the optical system is the Arizona Eye Model. [2]

  9. Optical transfer function - Wikipedia

    en.wikipedia.org/wiki/Optical_transfer_function

    The optical transfer function of a well-focused (a), and an out-of-focus optical imaging system without aberrations (d). As the optical transfer function of these systems is real and non-negative, the optical transfer function is by definition equal to the modulation transfer function (MTF).