A divergent laser beam was used to record holograms of moving iron fibers with submicron diameter (0.5 μm) and high velocity (125 m/s). Analysis based on geometric optics is used to derive the magnification factors for recording and reconstruction. Experimental results consisting of single-shot holograms of fast-moving fibers are presented. The divergent laser beam technique can be used for dynamic measure of particle size and fiber orientation distribution.