The full and reduced shell model calculations have been carried out for the light odd-even Sb-105 and Sb-107 isotopes. The model space has ben chosen as 1d(5/2), 0g(7/2), 1d(3/2), 2s(1/2), and 0h(11/2) for the full calculations and excluded 0h(11/2) for the reduced calculations. The reduced shell model calculations of Sb-105 and Sb-107 isotopes are presented for the first time. We obtain the energy spectra for the Sb-105 and Sb-107 isotopes in the full and reduced model space by using CD-Bonn two-body effective nucleon-nucleon interaction. The resulting energy spectra are compared to the experimental results to understand the effect of the 0h(11/2) level on the shell model calculations. We draw conclusions about the right model space in the shell model calculations for the isotopes around the N = Z = 50 region of the periodic table.