An optical measurement test setup was used to determine the elastic modulus of chemically bonded sand as it is used in foundry applications. The surface of the sand specimen was recorded by a stereo camera system during a 4-pointbending test. The images were used to calculate the material's deformation. Three different computational methods to determine Young's modulus were compared. One method was dependent on the displacement data captured by the test machine, and the other two methods were dependent on the data recorded by the optical system. All methods were used to characterize four different sand core materials with organic and inorganic binders. The optical methods are promising to yield more accurate results, as they measure directly on the specimen's surface.