According to the current concept, about 93 % of the Universe mass exist in the invisible form as the hidden mass (23 %) and dark energy (73 %). The hidden mass can reveal itself in interaction with electromagnetic radiation, and the effect of microlensing produced by compact bodies of galaxies is widely used in searching for the hidden mass. We consider substars, white dwarfs and main sequence stars as possible candidates for microlenses with taking into account that some microlenses may possess rather dense gaseous atmospheres. An analysis of focusing properties of microlenses was carried out on the basis of the model representations, and numerical estimates of magnification ratios were obtained in a wide spectral range — from optics to radio. A comprehensive investigation of characteristics of a particular microlens is needed for correct interpretation of observation data.