Search results
Results from the WOW.Com Content Network
Zoom lenses (sometimes referred to as "true" zoom) are ideally parfocal, in that focus is maintained as the lens is zoomed (i.e., focal length and magnification changed), which is convenient and has the advantage of allowing more accurate focusing at maximal focal length then zooming back to a shorter focal length to compose the image. [1]
The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century.
Cone of light behind an achromatic doublet objective lens (A) without (red) and with (green) a Barlow lens optical element (B). The Barlow lens, named after Peter Barlow, is a type of diverging lens which, used in series with other optics in an optical system, increases the effective focal length of an optical system as perceived by all components that are after it in the system.
The resolution of a microscope is defined as the minimum separation needed between two objects under examination in order for the microscope to discern them as separate objects. This minimum distance is labelled δ. If two objects are separated by a distance shorter than δ, then they will appear as a single object in the microscope.
The two dimensional image of a point source observed under a microscope is an extended spot, corresponding to the Airy disk (a section of the point spread function) of the imaging system. The ability to identify as two individual entities two closely spaced fluorophores is limited by the diffraction of light.
Léon Foucault developed a catadioptric microscope in 1859 to counteract aberrations of using a lens to image objects at high power. [2] In 1876 a French engineer, A. Mangin, invented what has come to be called the Mangin mirror, a concave glass reflector with the silver surface on the rear side of the glass. The two surfaces of the reflector ...
The viewer sees the images from both microscopes next to one another, as in the inset image. A comparison microscope is a device used to analyze side-by-side specimens. It consists of two microscopes connected by an optical bridge, which results in a split view window enabling two separate objects to be viewed simultaneously.
Afocal photography works with any system that can produce a virtual image of parallel light, for example telescopes and microscopes. Afocal photographic setups work because the imaging device's eyepiece produces collimated light and with the camera's lens focused at infinity, creating an afocal system with no net convergence or divergence in the light path between the two devices. [2]