Uhm....im also confused. How about purchasing in a fisheye lens. Or, use your 50mm and make your panoramic picture. Then in photoshop or some other editing program (the software that came with my moms kodak camera has many features including fisheye) and make it a fisheye after you take it. AAnd if you want an ultra wide lens, get a full fram body and a lens with a 180 degrees feild of view. Then you wouldnt need to stictch any pictures together, unless you want a 360 degree shot, then just turn yourself around and take another shot. 3 pictures would be the best.