The speckle photography method (single-beam speckle interferometry) was used to study the deformation of a high-density polyethylene film by determining the detail field of displacements in an enlarged image of the sample. The method is based on the analysis of changes in speckle patterns corresponding to two different deformation states, as the changes in the speckle patterns contain information about the change of the object. The displacement vector and Poisson ratio have been determined with an accuracy of 10% in the small deformation range (displacements of several microns). Limitations of the method, such as the range of measurable displacements, effect of image defocusing, and tilt of the sample, are discussed. Among advantages of the method are comparative simplicity (it does not require grating on the object surface) and the possibility of its application to larger deformations while maintaining the small deformation steps between two deformation states.