Comparison of IOs with various apodization for the same tilt of 25 arcsec. The blue curve corresponds to sharp-edge IO with R_IO = 1.694 mm, the red curve indicates the IO with R_IO = 1.662 mm opaque part and Δ = 0.1 mm gradient, and the green curve indicates the Δ = 0.2 mm gradient. The thin colored lines denote coronal signal with corresponding vignetting taken into account and vignetting functions (in the bottom part of the plot).