I was out taking photos of a waterfall in a shaded wood, standard lenses fitted, and a filter holder with105mm CPL fitted to take the reflections off the water surface. When I got home to edit them, I notice that there is a semi circle reflection ring on the lower part of a lot of photos, probably caused by light bouncing between the end of the lens and the CPL at the end of the filter holder. The sun was directly behind me at approx. 7pm in the evening. Ive never had this before. Is there a way to prevent it or was I just in the wrong place? I will try ad post and example shot later when I'm home.