What is meant by resolving power of an objective and how is that distinguished from resolution?
Resolving power of an objective refers to the ABILITY of that objective to yield an image which clearly separates points or lines lying close together in the specimen. The shorter the distance (between point or lines) the better the resolving power of the objective. Resolving power is related to the numerical aperture of the objective; the higher the numerical aperture, the better the resolving power.
Resolving power of an objective refers to the ABILITY of that objective to yield an image which clearly separates points or lines lying close together in the specimen. The shorter the distance (between point or lines) the better the resolving power of the objective. Resolving power is related to the numerical aperture of the objective; the higher the numerical aperture, the better the resolving power. The formula is expressed as: d = / 2N.A. or d = 0.61 / N.A. The former is according to Abbe, the latter according to Rayleigh. In the formula, d is the distance between two closely lying points; λ is the wavelength of light being used; N.A. is numerical aperture. Resolution is the ACTUAL separation achieved by the microscope system. For example, in Köhler illumination, the condenser diaphragm is usually closed down somewhat in order to effect a compromise between resolving power and contrast–to enhance visibility.
