70=20 0L 2.8 is.Exten tube or extender

hi just got the above and was going to get a 1.4 Kenko + 2 Canon extender.The manual states your able to use an extender tube.What is better extender tube or an extender?Do i need a filter (if so what kindor will the hood protect the lens?

Umm... extension tubes reduce the MFD and magnifies by letting you get closer. Extension tubes have no optics so they tend not to degrade IQ. Teleconverters like the Kenko 1.4x and Canon 2x have optics. They retain the MFD of the lens and pretty much magnify by the _x value. They serve sort of different purposes generally.

As for a hood... does it not come with one? As for a filter... some folks will say get one, some will say stay away from em. I say get a Protective Hoya HD filter, it is worth it IMO.