Canon supertelephotos

They were behind glass at Photokina, but they'll be on sale eventually: Canon's two new mammoth supertelephoto lenses. Canon just revamped its 300mm and 400mm F2.8 lenses and now is giving the same treatment to its even longer focal-length models with an F4 aperture. In addition, expect a focusing feature designed to help cinema users of Canon's SLRs in some of the lenses.