The contrast of the photospheric granulation in the centre of the disk at a wavelength of 500 nm has been determined by means of photographs taken during the solar eclipse of May 30th 1984. After restoration, values of 17.3% and 20.4%, using the sum of two lorentzians to define the instrumental profile, and of 11.7% and 14.3%, using the sum of two gaussians, have been obtained. This suggests that the results are quite sensitive to the particular choice which is made of the analytical approximation to the point spread function. The corrected power spectrum does not show significant differences to those of previous works. A comparison between the method for correcting the image degradation which the authors propose with those used by other investigators is also made.