1.6x + 2x = 320-1280mm
To quote Mazda: "Zoom Zoom!"
I just ordered a 2x extender for my camera bag. My primary plans are for using this with my telephoto zoom lens. Given my camera's built in 1.6 focal length multiplier, the new 2x extender, and my 100-400mm lens; I now have a 320-1280mm zoom potential. Very nice indeed! My lens is pushed back two stops and I loose auto focus but I've had some good practice since I've had a broken lens for a few months (I've since sent it in and am awaiting it back from the factory repair facility). I'm looking forward to trying to foray into wildlife photograpy, especially for my upcoming trip to Asia. Hopefully I'll get some great shots of tigers, elephants, monkeys, etc. that are truly "wild."