where can i get a reverse and how much is it?
I bought my reverse ring at the local shop for AU$40. You can get it off your local camera dealer or just on eBay.
The geniune
model from Nikon is the BR-2A, which fits ALL lenses with 52mm filter.
There are other sizes of reversal rings on eBay from the 3rd party manufacturers, I have no experience with them, so I cant compare the build quality between them. But the Nikon BR2A is made completely of metal mounts.
I'd need to use it with the 18-70mm DX that comes with the d70s...
No, I do not recommend you to use the 18-70 on a reversal setup. Even tho if you are allowed to put it on reverse with the ring setup, putting a zoom lense and more of a DX type zoom is disaster to the final image.
The basic setup and mostly used I have is the BR2A + Nikon 50mm f/1.8D lens. The 50/1.8 cost under AU$200 and you can get it off for roughly $150 I think. REAL SHARP lens, no need to say more.
As for now, I cannot find any other alternative that is cheaper and as good as this setup. You can use 1 lens for 2 purposes, how sweet is this. Plus, any other 52mm filter sized prime (no zoom) lenses can be used as macro with the ring!
In short here are some decisions for you:
Reverse ring: cheap and sharp. does not lose light on setup. loses focusing and metering (all manual exposure is fun and very challenging for beginners)
Close-Up Filters: cheap and easy to use. does not lose light. loss of sharpness, quality and some distortion may occur.
Extension rings: relatively cheap. easy to focus and meter. loss of light through the tubes makes exposure longer and require tougher light setup.
Dedicated Macro lens: ALL (yes ALL) of the ++posivites above. At expense of your wallet's weight or potential bashing from wife
There are some shots from the past I took with the reversal ring. The gallery at my sig bellow. The "Water Drops" were one of most famous of them all.
I hope this cleared up some of your questions. But have made you harder to choose which setup from?