There are various general considerations when buying a macro lens.
What is compatible with my camera?
Nikon's macro lenses include the word
Micro in their name and their current line up can be found here. From those you would need an
AF-S lens or you will not be able to use autofocus.
What level of magnification are you looking achieve? The smaller the object you wish to capture, the larger the focal length (
mm) you will need to fill the frame.
How close do you want to get? Again, to fill the frame you'll want to be able to alter position, the minimum focus distance (MFD) will determine how close do you can get.
How much are you willing to spend? That is a question only you can answer. Macro photography is a relatively small market and so macro lenses are rarely cheap. Like anything in photography, detail in production counts for a lot and if you want good equipment you will need deep pockets.
There are some ways to slim down the costs. You can:-
- look at other lens makers like Sigma and Tamron. Both produce some good lenses.
- buy a cheap (2nd hand) fully manual (or
AF-D) lens in combination with a reverse ring or mount. This can be fiddly to begin with, but as this example shows, can be highly effective with practice.
- add extension tubes between your existing camera body and lens.
You can also get additional elements (similar to filters) which attach to the front of your existing lens, however these are usually of very poor quality and should be avoided.