Rich Lewis from New Jersey R1/R10 Lens Ring
3 stars - Nodal Ninja R1/R10 Lens Ring for Canon EF 8-15mm f/4.0L Fisheye USM Lens - Not a Perfect Design But Works Great. About Me Pro Photographer. Verified Buyer. Whoever designed this concept of mounting the panorama head right to the lens did a great and not so great thing. The great thing is that the ring is specific to one lens so the nodal point is easily set. It also makes setting up a 360 panorama very easy. The down side is that the ring covers the AF/MF switch, Zoom Lock and Manual Focusing Scale. There is probably no better way to do this. If you leave this ring on the lens it increases the weight and makes it a little difficult to carry and store. Here is a tip. They recommend using tape to hold the inner ring on to the lens. My experience is that this is totally not necessary. Yes, I would recommend this to a friend. - By Rich Lewis from New Jersey
NN note - this lens ring is now available with viewing window as requested above.