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Difference between revisions of "Light microscopy"
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==Resolution== | ==Resolution== | ||
<math>R = 1.22 * {gamma \over {NA_{obj} + NA_{cond}}}</math>.<ref>{{cite web |url=http://www.life.umd.edu/CBMG/faculty/wolniak/wolniakmicro.html |title=Principles of Microscopy |author= |date= |work= |publisher= |accessdate=21 January 2011}}</ref> | <math>R = 1.22 * {gamma \over {NA_{obj} + NA_{cond}}}</math>.<ref name=pom>{{cite web |url=http://www.life.umd.edu/CBMG/faculty/wolniak/wolniakmicro.html |title=Principles of Microscopy |author= |date= |work= |publisher= |accessdate=21 January 2011}}</ref> | ||
<br> | <br> | ||
Where: | Where: | ||
*R = resolving distance; smaller better. | *<math>R</math> = resolving distance; smaller better. | ||
* | *<math>NA_{obj}</math> = numerical aperture of the objective; typically 0.25 - 1.4, >1.0 is oil immersion, it is usu. inscribed on the lens itself. | ||
*gamma = wave length of light. | *<math>NA_{cond}</math> = numerical aperature of the condenser. | ||
*<math>gamma</math> = wave length of light. | |||
Closure of the condenser diaphragm results in a loss of resolution, i.e. R is larger.<br> | Closure of the condenser diaphragm results in a loss of resolution, i.e. R is larger.<ref name=pom/><br> | ||
===Numerical aperture=== | |||
<math>R = 1.22 * {gamma \over ( D/2*f )}</math>. | <math>R = 1.22 * {gamma \over ( D/2*f )}</math>. | ||
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*D = diameter of entrance pupil. | *D = diameter of entrance pupil. | ||
At infinity: | At infinity:<br> | ||
N = 1/(2*NA_i). | <math>N = 1/(2*NA_i)</math>.<br> | ||
f/D = 1/(2*NA_i) | <math>f/D = 1/(2*NA_i)</math>.<br> | ||
<math>f/D = 2*NA_i=D/f</math>. | |||
N ---> smaller number = larger opening. | N ---> smaller number = larger opening. | ||