Hutech dropin front filters:
http://www.sciencecenter.net/hutech/...pics/ha-ff.jpg
http://www.sciencecenter.net/hutech/canon/index.htm
Astronomik dropin front filters:
http://www.astronomik.com/english/en...ip_system.html
(they do
300D, 350D, 400D, 450D, 20D, 20Da, 30D, 40D)
Anyone using these , are you happy with their performance ?