Another attempt with macro lenses. This would seem to show equal DOF, from 150 and 100 mm lenses. I put a blob mid ruler and used it to gauge image size against a focusing square in the viewfinder. It still took some playing around to get the shape exactly the same size in both shots.
Base view is the 150 mm lens, the 100 mm image was shifted right and masked to show.
I don’t think I mentioned it here but as you focus lenses the focal length shifts a little so the actual focal lengths are probably not exactly 150 and 100 mm, they should be close though.