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Two Leica oil immersion microscope objective lenses; left 100×, right 40×. The objective lens of a microscope is the one at the bottom near the sample. At its simplest, it is a very high-powered magnifying glass, with very short focal length. This is brought very close to the specimen being examined so that the light from the specimen comes ...
With any telescope, microscope or lens, a maximum magnification exists beyond which the image looks bigger but shows no more detail. It occurs when the finest detail the instrument can resolve is magnified to match the finest detail the eye can see. Magnification beyond this maximum is sometimes called "empty magnification".
Defining equation SI units Dimension Lens power P = / m −1 = D (dioptre) [L] −1: Lateral magnification m = / = / dimensionless dimensionless Angular magnification m = / dimensionless dimensionless
When the imaging system obeys the Abbe sine condition, the ratio of the sines of these angles equal the (lateral absolute) magnification of the system. In optics , the Abbe sine condition is a condition that must be fulfilled by a lens or other optical system in order for it to produce sharp images of off-axis as well as on-axis objects.
The area provides a reference unit, for example in reference ranges for urine tests. [3]Used for grading of soft tissue tumors: Grading, usually on a scale of I to III, is based on the degree of differentiation, the average number of mitoses per high-power field, cellularity, pleomorphism, and an estimate of the extent of necrosis (presumably a reflection of rate of growth).
With no modification to the microscope, i.e. with a simple wide field light microscope, the quality of optical sectioning is governed by the same physics as the depth of field effect in photography. For a high numerical aperture lens, equivalent to a wide aperture, the depth of field is small (shallow focus) and gives
The ratio of the focal length of the objective and the eyepiece, when mounted in a standard tube length, gives an approximate magnification of the system. Due to their design, compound microscopes have improved resolving power and contrast in comparison to simple microscopes, [ 11 ] and can be used to view the structure, shape and motility of a ...
In microscopy, NA is important because it indicates the resolving power of a lens. The size of the finest detail that can be resolved (the resolution) is proportional to λ / 2NA , where λ is the wavelength of the light. A lens with a larger numerical aperture will be able to visualize finer details than a lens with a smaller numerical ...