Variations in the model parameters with the filtered relative amplitude, γ. (a) The parameters α_s, α_a, and β (in percent of the incident flux) as functions of γ, see Eqs. (77a)-(77c). (b) Radial cut of γ for a flat wavefront and pinhole diameters from 0.5 to 4 λ/D. (c) Mean value of γ in the pupil for a phase aberration with taking values from -π/2 to π/2 and whose shape is one of the fifty first Zernike modes, for a λ/D pinhole. Below the curve we show the PSFs in logarithmic scale for Z₁, Z₂, Z₄, and Z₂₅. The pinhole diameter is overlaid with a black circle. The percentages indicated for each Zernike mode corresponds to the PSF energy encircled within the pinhole.