Zoom in lens for nikon d5100?

I'd like to get a zoom in lens for close up video and photo shots of nature squirrels ect…
i only have the 18-55mm and i want something that will zoom in more

What you want is a Macro lens (Nikon call them, 'Micro,') a prime lens which focuses very close, Nikon, Sigma and Tamron all make them, but they're expensive - google for prices etc.

A cheaper option is a set of extension tubes - which move the lens further from the film plane.

Note that a zoom lens can do close up somewhat, but they are not macro lenses. If you want to shoot really close, it takes a macro. However, if you are looking at squirrels, then something like a 55-300mm would work fine.

You could get a squirrel close up full-frame with the 55-300mm, but since this lens is not a macro, you would not be able to get a tiny bug full frame (but I'm not sure if that is what you want).

One last comment about macro. There are no zoom macro lenses. Those that claim to be (Sigma), are not true macro, but more of a close-up feature.

True macro is a macro 1:1, meaning that the macro is life size. Only prime (fixed focal length) lenses that say macro 1:1 are true macros. Sigma zooms are often macro 1:2.5 or so, which classifies them as close ups rather than macro.

If you are confused about all of this macro 1:1 stuff, here is a more in-depth explanation:

http://www.althephoto.com/lenses/100mmprime.php

If you are looking at doing true macro on the cheap, look at the Nikon 40mm micro. It is inexpensive (<$300), at least for a macro lens. The disadvantage is you have to get awfully close to do 1:1 macro, so close that you might scare away bugs. The advantage though is that it is Depth-of-Field friendly.

I have two macro lenses. The Nikon 40mm micro, and Tokina 100mm macro. I use the 100mm for my bugs, and the 40mm for everything else. Actually, I started out with the Tokina 100mm, but my son (who has a D3000), bought the 40mm micro, and I was so impressed with it that I bought one too.

I see an application for both really. But realize that when you go to 100mm, you need a tripod, a macro flash, and the cost starts raising quickly.

Another answerer suggested you buy a macro lens, but I don't agree - you're not going to be able to get close enough to squirrels or birds etc to need a macro lens. A 55-200 VR or 55-300 VR are fine for your needs.