This paper deals with the experimental determinated forming limit diagrams at the necking of thin aluminum sheets obtained by the application of a new method of necking detection and strain measurement based on digital image analysis. The two analyzed images usually correspond to the initial, unstressed specimen and the image just before the necking. The forming limit diagrams were obtained using direct strain path and complex strain paths. The result obtained indicates that the forming limit diagram strongly depends from strain path and state of stress applied.