The 28-280 has more of a zoom range (you can zoom out farther). Without knowing specifics of the lenses, like apertures and the companies that made them, it's hard to tell which is made better. One might suit a particular shooter's needs more than the other. What kind of pictures do you want to shoot mostly?

You know the lenses are not made for the same kind of camera, right? Or at least last I knew, Panasonic didn't make lenses for a Canon. What kind of camera will it be for? Or are you deciding on a camera based on the lens?

Anyway, I'd go with the Canon lens. They are among the best in lens makers. I hope you have a Canon camera to put it on!

The Difference Is Focal Length

The 28-105mm Lens Is A Much Shorter Focal Length

Than 28-280mm, understand?

What brand are these lenses? Are these lenses for an SLR or are you talking about the focal length of point-and-shoots? What are your need?

Without knowing the specifics I can't say much. The 280 has the advantage in that you can get closer to far-away objects. It also has the advantage in that you have a nice wide range of focal lengths which makes it a good walk-around lens.

One disadvantage of the 280 is probably the quality. One of the trade-offs of having a wide range of focal lengths is that it usually results in one lens trying to do too much and thus being inferior in build and picture quality. Usually you don't want to buy a lens that has more than a 5x zoom and that one's a 10x (280/28 = 10).