For shooting a pictures, should i use Manual Focus & Auto Focus in Nikon D3100?

Hi, i just bought a Nikon D3100 + 18mm- 52mm Vr lens, i want to know for take a closer pictures ( macro photography ) should i use Manual Focus or Auto focus? What will different in result?

I'd try manual for the effect you are looking for. At least till you get a feel for the results. That's the beauty of digital photo, easy to delete.

Close Focus

0.9 feet (0.28m) from the image plane (the back of the camera). This is only inches away from the front of the lens!

When using a macro lens, shooting in manual focus mode is preferred. You have much more control over what parts of the image is in focus.

When shooting anything else, auto-focus makes things a lot easier, especially when shooting moving things like action, sports and some wildlife

Manual focus is better for Macro. The camera will not get it right most of the time in autofocus. That's because with Macro, depth of field (DOF) is very shallow. The camera will not know what to focus on exactly.

There are several times when manual focus is preferred over autofocus.

Macro is almost always manual focus.

Fireworks, lightning, and other quick occurring scenes where the objects are distant is better when using manual focus.

Fast objects sometimes works better with manual focus as the camera's focusing system may not be able to keep up.

Learn to use manual focus in many situations. The reason that manual focus switch is so conveniently located on the lens is because it should be used occasionally.