Phase conjugation with high quality can be obtained by stimulated Brillouin scattering in the focused beams' scheme, even when the in homogeneous pump light contains a self-focusing strong component. The scattered light originates from the selftrapped filament regions. The conjugation fraction η depends on the intensi ty ratio a of the strong component and the total incident light, attaining a maximum ηmax (=80%) at a certain value of σ. By taking in-tc account the effect of self-focusing on η(σ), a fair agreement with experiments is obtained.