EF 100-400mm f/4.5-5.6L IS USM RRP $3,499.00 . So more expensive then the EF 400mm f/5.6L USM RRP 2,699.00 .These are in Australian dollars. The thing with the extenders is that quality is lost. Even though alot less the price i think i would be eventually disappointed with it:(. Another friend thinks that Sigma Lens might be the go. As yet i have tried to only stick to Canon brand. I use Canon EOS 20D. So to change brands will i loose quality? What is your view on cheaper brands? Are we paying for the brandname on certain lens or is the quality better? Thanks for your help Chris:)