Plane-wave X-ray topography experiments were carried out at a 200 m-long beamline, BL20B2, at SPring-8. Relatively high-energy X-rays of 30 keV with an angular divergence of about 0.01 arcsec were produced by using only one collimator crystal. FZ-Si and CZ-Si wafers were characterized in transmission geometry (Laue case). Clear oscillatory profiles in rocking curves of the FZ-Si crystal were observed. Plane-wave topographic images of dislocations, growth striations and grown-in microdefects in the CZ-Si crystals were obtained. The dependence of the topographic images of the lattice defects on the sample-photoplate distance was also studied.