Situation: I am setting up a Vignette effect for my scene. Like what I do normally, I have a lens distortion node, math node (set to 'greater than'), blur node, and a mix node (set to multiply).
Problem: However, for this scene, the vignette effect seem to have a weird shape and it's not symmetrical either. Below is the result. How do I fix this? Thanks. Here is my blend file