This paper is concerned with dynamic force identification on thin plates from full field vibration measurements. The main goal of this study is to compare two force identification methods. The first method is the Force Analysis Technique (FAT). It uses a finite difference scheme to discretize the Love-Kirchhoff spatial operator and then resolve the local equation of motion to identify the load. The second method under consideration is the Virtual Fields Method (VFM). In this technique, virtual displacements and curvatures are used to solve the principle of virtual work (PVW). The local aspect and the fact that boundary conditions of the plate need not to be known a priori are important advantages of both methods. In this paper full field vibration measurements are obtained by optical deflectometry. The paper first gives an overview of the Force Analysis Technique, the Virtual Fields Method and the optical deflectometry techniques. It then presents experimental results based on deflectometry measurements.