I recently started using STC dual narrowband clip in filter on my Fuji camera. I realized there was slight halo around the center of the frame. I was checking the flat frames and could see a faint black circle in the middle with light halo around it. Exacerbated it with tone curve. Any ideas what could be causing this? It shows up after stacking the pictures. Attaching the blue picture with filter on the camera (shot with Fuji 55-200mm lens at 200mm, 2 minute exposure) and the yellow picture without the filter from few weeks ago (using Fuji 100-400mm at 400mm for 30 seconds). Both shots taken with Fuji XT30 at ISO 3200.
You can also see that halo around Orion Nebula picture I took with this filter (taken with 100-400mm at 400mm with 30 second exposures)
Edited by palamrinder, 19 January 2021 - 02:15 PM.