Comparison of the excess deflection appearing for a squared truncation with deflection associated to a shear. Left: Δκ map for a squared truncation and underlying NIE density profile. Middle: α_x map created using FFT convolution for Eq. (6) using Δκ. Right: difference between α_x map created using Δκ (middle) and α_x map from a shear; the hatched region is the 3″-radius region where the lensed images are formed.