This paper describes a comparative study of reconstruction algorithms from sequences of images, comparing algorithms which make the weak perspective assumption (also called scaled orthography or para perspective) to algorithms assuming perspective projection. The weak perspective assumption is usually employed to simplify the computation. Using three sequences of real images, taken under conditions corresponding to small, medium, and large fields of view, we compare two algorithms that compute invariant shape from motion; one assumes scaled orthography and one assumes perspective projection. The paper describes also a joint algorithm, which combines the simplicity of weak perspective algorithm with the accuracy of the perspective one.