I have sent a personal message to Sueann on a couple I have used, including Digitalrev from here (which I have used), which I have found to be good and have good prices. I am only linking to these places as they generally have a page dedicated to "wide zooms" and also "tele zooms" etc which makes it easier to compare brands. I have absolutely no personal interest in any of them as I actually purchase nearly all my gear from a local Sydney store as I like personal service and the back up they provide.