: what are these Series VII fisheyes you speak of? What's the conversion rate? Does it vignette? Where can you get one? Are they 58mm threads or do you need a stepup or stepdown ring?
I have a large collection of .42X cheap Series-VII fisheyes, all different, most no-name and uncoated. Matching of particular fisheyes with particular camcorders (and playing a bit with lens-fisheye spacing) is necessary for best image quality - there is not one I can name that works well on all the camcorders I've tried them on. The one I have that works well on the VX-2000 produces a circular image (with top and bottom of the circle cut off by the frame edges). It has a VERY wide angle of view, and I find it quite useful, but I would also like to find a good full-frame version (and a good zoom-through .5X, also). Still looking... With the fisheyes, some I adapt directly with Series-VII to XXmm rings, some I equip with my standard-thread 52mm adapter, then step that to the lens thread size needed.