A focusing method for an optical instrument for magnified viewing of an object includes producing at least two images with different focal positions and applying several different sharpness functions. Each function has an absolute extremum which specifies the optimum focal position to be set for the viewing and which lies in a close focus range of the sharpness function adjoined on both sides by a far focus range which contains local secondary extrema. For each of the at least two images an evaluation thereof is performed with the focal position as a variable such that a sharpness function variation direction of the focal position is calculated for each sharpness function in order to arrive at the optimum focal position. A determination is made for main variation direction based on all sharpness function variation directions, which is then used during further focusing.