Canon USA authorized dealer Adorama has a great deal on old version of Canon EF 100-400mm f/4.5-5.6L IS USM lens. This is currently lowest price for this lens.
Canon EF 100-400mm f/4.5-5.6L IS USM lens – $999.99 – at Adorama.com
Regular price for EF 100-400mm f/4.5-5.6L IS USM lens is $1,299 at most US stores.
See 4.5/5 reviews at Amazon.com
The new version of EF 100-400mm II is $2,199.