Radiative effects in semi-inclusive hadron leptoproduction of unpolarized particles are calculated within the leading order approximation. The contributions of the infrared-free sum of the effects of real and virtual photon emission as well as the contribution of the exclusive radiative tail are considered. It is demonstrated how the obtained formulas in the leading log approximation can be obtained using the standard approach of the leading log approximation as well as from the exact expressions for the radiative correction of the lowest order. The method of the electron structure function is used to calculate the higher order corrections. The results are analytically compared to the results obtained by other groups. Numeric illustrations are given in the kinematics of the modern experiments at Jefferson Laboratory.