ocean

This is a great Red Ring Canon Lens.Probably my favorite.No external parts moving in or out.The only moving parts are the focus and zoom rings.No push pull,like the 100-400.I use the 100-400 a lot for bird photography,but it doesn't get as much light as this lens.I put a 1.4x II extender on this sometimes,which moves the f-stop up to 4.It really makes no difference unless I am in low light situations.I really like the image stabilization on this lens.The 2 IS modes.1 for regular shooting and 2 for panning which works great at airshows.If you decide to get an extender.Get the 1.4 instead of the 2x.With the 2x there is no AF.I just noticed that you have the 70-200mm 4L lens instead of the 2.8.Still a great lens.Especially with the 1.6x crop factor,19 effective megapixel,18 recorded mp's APC-S CMOS sensor and the dual digic 4 processors on the 7D.I wish my 1Ds had the DD4 processors,and the 920,000 tft LCD Display.I'm sure they will put it on the 1Ds Mark IV when it comes out.Anyway,this is a great piece of equipment,especially on that sweet 7D.Have a good one.