[en] In the framework of lectures on quantum chromodynamics deep inelastic scattering of leptons on nucleons is considered. To describe the deep inelastic scattering a formal approach of field theory is applied. In the framework of a parton model the process of lepton pair production is investigated. The cross section of the process is determined. At great values of four momentum transfer to hadrons by leptons the difference from the parton model have been observed, which are explained by quantum chromodynamics. These differences logarithmically depend on the q value