Carl Zeiss Lenses http://www.zeiss.com/photo
Cosina / Voigtlander http://www.cosina.co.jp/
Dineonline http://www.dinecorp.com/
Kenko http://www.thkphoto.com/products/kenko/index.html
Noktor http://noktor.com/products.php
Samyang Lenses http://www.syopt.co.kr/eng/product/manual_zoom.asp
Schneider Lenses http://www.schneider-kreuznach.de/foto/foto.htm#
Sigma Lenses http://www.sigmaphoto.com/
Tamron http://www.tamron.com/
Tokina http://www.thkphoto.com/products/tokina/index.html