I am wondering of anyone knows of photographers with books which incorporate nature or macro photos taken with fisheye lenses? I know this sounds unusual, but I was interested in the perspective and close-focus of some of these lenses, which in some cases is a few cm's. My second question in, is anyone familiar with the 180-degree accessory lens fisheyes? I just found one made by Kenko, but don't have instructions. I was just going to play around with it to learn about it, but this was not so easy. When I install in on my Ftb, I cannot see the meter. Also, I do not know which aperture to use, nor how to determine exposures. I have heard this lens gives a circluar image, but it does not at all look circular in my viewfinder with my Canon 50mm lens. Is it also true that this lens can be used on lenses other than the normal lens? I have many questions! One last one is how do you get to use a filter on such a device or is this impssible? Any information would be great. I am hoping to put the lens neartly on the ground, or, with larger and taller subjects, put the camera on the ground facing up. Thank you.