Bolometric amplification of a static source for selected distances from the lens seen by an observer at infinity as a function of Δϕ. Top: wide range of Δϕ covering the first 12 images and first six Einstein rings. Peaks at Δϕ = 1,  3,  5,  … (2,  4,  6,  …) arise when the a source located exactly on the caustic line behind (in front of) the lens. Bottom: bolometric amplification of sources at short distances for a smaller range of Δϕ angles, encompassing the first amplification peak.