In a magnetic resonance system and an operating method therefor, a B.sub.1 field distribution of a radio-frequency antenna is measured in at least one part of a examination volume of the magnetic resonance system, and then the RF pulses emitted by the radio-frequency antenna are optimized, based on the determined B.sub.1 field distribution, for homogenization in a specific volume. An effective volume within the examination volume is determined beforehand for each applied RF pulse and, based on the determined B.sub.1 field distribution, the appertaining RF pulse is individually adjusted such that the B.sub.1 field is homogenized within the effective volume of the RF pulse.