Charged-particle beam pattern transfer apparatus and charged-particle beam optical systems are disclosed. A representative charged-particle beam pattern transfer apparatus comprises a projection lens that images patterns from a mask onto a substrate. To reduce off-axis image aberrations, especially anisotropic coma and astigmatism, deflectors are provided that produce a magnetic field such that the effective optical axis of the lenses is along a straight line that is tilted with respect to the mask and the substrate. Focus correctors are provided that produce a magnetic field that corrects image focus. Mathematical descriptions of these magnetic fields are disclosed. With such magnetic fields, the charged-particle beam that irradiates a central region of a subfield on the mask propagates along a straight-line axis through the projection lens, reducing deflection aberration and improving image quality.