The Sony wide angle lens never comes off this camera, but although it is quite sharp, it is very susceptible to flare. The Cokin sunshade, when modified with the fabric donut, completely eliminates flare and hotspots in the images.
The Cokin sunshade which snaps on to the filter holder is useless without the fabric cover, since it admits light through the back and top of the shade. The fabric is simply two pieces of elastic material, available at any sewing supply store. A two-inch piece and a one-inch piece are sewn edge to edge and the whole assembly sewn end to end, to make a continuous loop. Because it's stretchy, it holds to the square sunshade quite well, although I attached two small pieces of the "hook" side velcro to ensure it doesn't move.