Abstract: A method for determining a depth of a vapor capillary during laser machining includes: irradiating a machining laser beam onto a workpiece to form the capillary, the beam deflected by a first deflection device along a machining path within a first scan field, irradiating an optical measuring beam onto the workpiece, the measuring beam deflected by a second deflection device relative to the machining laser beam along a scanning path within a scanning area and then together with the machining laser beam by the first deflecting device, acquiring measured distance values along the path based on part of the measuring beam reflected by the workpiece, determining a depth/position of the capillary based on the acquired measured distance values. The scanning area size is based on a position of the laser beam and/or deflection of the laser beam by the first deflection device. A corresponding laser machining system is also provided.