I included this image even though badly over exposed because it clearly shows that shadows are not hiding a yellow eye ring which shadows can do. When I digiscope in cloudy conditions I use a high iso, probably 2000 or 1600 in this shot and try to maintain 650 shutter to prevent blur. But if not paying attention one can over expose if the sun comes out even a little which was the case in about 20 or so shots until I realized and changed the iso.