was redder than I thought, but this was the cause. As line of sight approaches the glazing angle, the transmitted light will be colored. This is a gif that switches between with and without ND, but the color at the edge is different even though the center is the same. If you happne to shoot the sun on the edge of ND, it turn into redder light source than actual.. Supplement 1 If you shoot the sun at the center of the frame and stitch it with PTGui, you can ignore this problem. However, in a location with multiple streetlights, it is difficult to frame all of them on center, so if you are worried about flicker you may have to resort to ND filters. I expect this problem is likely to occur with high density ND filters. Supplement 2 I wanted to consider a drop-in filter, but if I put the drop-in filter between the Sony camera and the Canon lens, there is an electronic contact problem. I kept it off because there was a risk that I could not control the aperture of the camera. Also, since there are no drop-in filters on the market that dim light by 12 EV, I think you can consult with an optical manufacturer about the same diameter filter if necessary.