Dslr lens help.i need some about what things mean?

So i'm a kinda still new into photography. I'm looking at a lens but i need help with what some things mean. Nikon - 70-300mm f/4.5-5.6G ED-IF AF-S VR Telephoto Lens is the lens in question. I don't know what the difference is form the 70 to 300mm and the 55 to 300mm. If some one can answer that. Also what dose the f/4.5-5.6G ED-IF AF-S mean. I have no idea i could really use some help.

I can answer about half of this… The 70mm to 300mm is the size of the lens. The f/4.5 is the f stop which basically is the opening or aperture thy let's light into the camera. The AF stands for Autofocus.

70-300mm or 55-300mm is the focal length of the lens. (i.e. How much it can "zoom")
f/4.5-5.6 is the variable aperture, meaning that at 70mm, the largest aperture you can set is f/4. At 300mm, the largest would be f/5.6.
I'd suggest reading this to understand a bit more about lenses: http://www.cambridgeincolour.com/...lenses.htm

And this link should help you with the letter acronyms and whatnot: http://www.kenrockwell.com/...kortek.htm

70-300mm Focal length of the zoom lens from medium telephoto to long telephoto, great for shooting sports, action and wildlife

f/4.5-5.6G At 70 mm the aperture is f/4.5 and at 300 mm it is f/5.6.

ED - ED is a very high quality optical glass.

IF - means that it is internal focus, so the end of he lens does not turn when you focus it.

AF-S is the latest and greatest, ultra fast auto-focus system on Nikkor lenses

VR - is the vibration reduction scheme that allow hand holding long lenses without causing image blur

The 70-300 mm is a better lens than the 55-300 mm in many ways