The Canon EW-83DII from the 24mm 1.4 L is better apparently, as long as you are using a 1.6 X body.
Not cheap though for a piece of plastic, about £40 amazon
http://www.amazon.co.uk/exec/obidos/...081802-3198216
or the usual ebay sellers
http://cgi.ebay.co.uk/Canon-EW-83DII...QQcmdZViewItem
Certainly looks better than the 'saucer' that is supplied with the 17-40.
Not tried one myself yet, so who is going to order one
?
edited to ad,
How about a proper bellows shade such as Lee
http://www.tyi.ca/SalesOrdersHoods.htm
A bit spendy though !
Mark.