
http://www.juzaphoto.com/eng/articles/canon_300_4-sigma_100-300_canon_100-400.htm
http://images.google.cz/images?gbv=2&hl=cs&q=lens+scheme&sa=N&start=0&ndsp=21
http://www.juzaphoto.com/eng/articles/canon_70-200_sigma_70-200_tamron_canon_100-400.htm
http://dpinterface.com/reviews/canon-eos-1d4-preview/gallery/A00A0844.JPG
http://aux1.jp.canon.com/eosd/samples/eos1dm4/downloads/005.jpg