1. A method for generating a two-dimensional x-ray projection image that is free of parallax error using a C-arm system comprising a C-arm on which an x-ray source and a radiation detector are mounted opposite each other, said x-ray source emitting, from a focus, an x-ray beam having a solid angle, said method comprising: acquiring image data with said radiation detector from a projection region of a subject located between said x-ray source and said radiation detector, said projection region being larger than a maximum projection region covered by said solid angle of said x-ray beam when said x-ray beam is stationary, by irradiating the subject with said x-ray beam to acquire at least two individual projection exposures of the subject with said focus of said x-ray source being stationary relative to said subject and with said solid angle being modified respectively for acquiring said at least two individual exposures; acquiring said image data in at least three individual exposures and by causing said C-arm, between said at least three individual exposures, to execute a first movement comprising a combined rotation around a middle point of said C-arm orthogonal to an orbital plane spanned by said C-arm and a translation orthogonal to said orbital plane, and a second movement comprising a combined rotation around said middle point of said C-arm in said orbital plane, and a translation in said orbital plane; supplying said image data to a processor and, in said processor, generating a complete exposure of an entirety of said projection region from said at least two individual exposures, said complete exposure being free of parallax error due to said focus being stationary while acquiring the image data respectively for said at least two individual exposures; and in said processor, generating a data file representing said complete exposure and making said data file available at an output of said processor in electronic form.