An apparatus, system and method for measuring straightness of components of rotating assemblies are described. A digital mapping system for measuring the straightness of a shaft of an electric submersible pump comprises a light emitting micrometer. A method for measuring the straightness of components of rotating assemblies comprises providing a controller with acceptable deviation parameters for a component to be measured, surface mapping the component using a light emitting micrometer, electronically identifying bent locations on the component that exceed the acceptable deviation parameters, and measuring circumferentially at the bent locations with the light emitting micrometer to determine the magnitude of the bend. An apparatus for measuring a component of a rotating assembly comprises a light emitting micrometer configured to map the surface of a component and a range finder coupled to the micrometer for determining the location of the micrometer during measurement.