Hi, I was trying out my new Canon 100-400mm lense in Shenandoah National Park recently. Love this lense for photographing birds and wildlife. When I tried to shoot the sunet with the center of the sun a few degrees above horizon, the images consistently have reflective spots. With my wide angle or canon kit lenses, no reflective spots on the image. I'm obviously trying to enlarge the sun in the photos. Is there something I'm doing wrong? I am not using any filters. (I take precautions to protect my eyes and to protect the camera while waiting for the right setting.) Thanks in advance!