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  2. Parfocal lens - Wikipedia

    en.wikipedia.org/wiki/Parfocal_lens

    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]

  3. Optical microscope - Wikipedia

    en.wikipedia.org/wiki/Optical_microscope

    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.

  4. Oil immersion - Wikipedia

    en.wikipedia.org/wiki/Oil_immersion

    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.

  5. Fourier optics - Wikipedia

    en.wikipedia.org/wiki/Fourier_optics

    Fourier optics begins with the homogeneous, scalar wave equation (valid in source-free regions): (,) = where is the speed of light and u(r,t) is a real-valued Cartesian component of an electromagnetic wave propagating through a free space (e.g., u(r, t) = E i (r, t) for i = x, y, or z where E i is the i-axis component of an electric field E in the Cartesian coordinate system).

  6. Microscopy - Wikipedia

    en.wikipedia.org/wiki/Microscopy

    Antonie van Leeuwenhoek (1632–1723). The field of microscopy (optical microscopy) dates back to at least the 17th-century.Earlier microscopes, single lens magnifying glasses with limited magnification, date at least as far back as the wide spread use of lenses in eyeglasses in the 13th century [2] but more advanced compound microscopes first appeared in Europe around 1620 [3] [4] The ...

  7. Plane Passenger Allegedly Caught with $238K Worth of Cocaine ...

    www.aol.com/lifestyle/plane-passenger-allegedly...

    A narcotics canine then gave a “positive response” to the odor of the wheelchair, which prompted an officer to conduct an “intrusive exam” by drilling into the cushion.

  8. Optical transfer function - Wikipedia

    en.wikipedia.org/wiki/Optical_transfer_function

    Although typically only a one-dimensional, or sometimes a two-dimensional section is used, the three-dimensional optical transfer function can improve the understanding of microscopes such as the structured illumination microscope. True to the definition of transfer function, () = should indicate the fraction of light that was detected from the ...

  9. North Korea's Kim says weapons without ideology are 'ironware ...

    www.aol.com/news/north-koreas-kim-says-weapons...

    North Korean leader Kim Jong Un said the country has come a long way in building a powerful army but weapons without ideology are simply "ironware", as he stressed loyalty to some of its most ...