Primary amplification peak of a static source. The bolometric amplification of the first direct image, ℳ_a+, is shown as a 3D function of the source distance, R, and the angular separation ψ. Different lensing regimes are indicated. The magenta dashed line denotes the source distance of the maximal amplification at fixed ψ, R_max. The red line at R_e = 200M separates the region of extreme gravitational lensing regime and the region of WDL validity. The blue line denotes the source distance, R_ws(ψ), separating the region of the strong lensing regime () and the region of the weak lensing regime (). This boundary between the two regimes corresponds to the constant value of the bolometric amplification, ℳ_a+ = 1.17047, for ψ ≤ 10⁻².