If the field is defined in terms of angles, the normalized field coordinates Hx and Hy are defined differently than for other ZEMAX features. In this case only, Hx and Hy correspond to divisions on a uniform projected grid in object space, centered on the reference field coordinate. These normalized field coordinates are defined as: 0I-9nuw,^; H = tan (q) / tan (qm) jodIv=C k{R> where q is the angle relative to the reference field chief ray and qm is the maximum normalized field angle.