Nikon d5100 & manual macro tube extension?

I have recently bought a macro extension tube for my nikon d5100 with 18-55mm lens? But for some reason after adding the extension tube between the camera n lens its dark n blur when i look through it and on the camera screen it says lens not fitted or attached. Any idea? Please advice. How do i make it work and how i set it up interms of getting rid of the drk blurness n even if i have to use it in manual mode but how exactly? Even if i manual focus its blurr so i'm guessing there's no way its compatible with mine.cheers

These extension tube sets claim to be able to maintain electronic communication between lens and camera:
http://www.bhphotovideo.com/...e_Set.html

http://www.bhphotovideo.com/..._tube.html

The set that you have does not. Return it.
For your set to be potentially useful, you would have to be in fully manual M mode. And then it still won't work, because your lens is a G lens which has no mechanical aperture ring and was designed to be set electronically from the camera body, which it can't do with the cheapo tube set.

Even with a properly functioning tube set, your lens is not optimized to give great image quality focused that close, so it would be better to save your money towards a real macro lens. Of course even with that, to get good results you need a good tripod with good adjustability such as a tiltable or reversible column, plus an external flash that can be used for bounce flash. Of course those items are useful even if you don't do macro.

Some reason you don't like the answers you got an hour ago with the same exact question?

Also keep in mind that with the extension tube attached, you need to have the lens at or near the minimum focusing distance. Then at which point you'll get things in focus that are about six inches to one foot in front of the lens and only in that range. With the extension tube attached, no lens will focus to infinity which may explain why everything is blurry.

You still haven't figure it out?

The 18-55mm has no aperture ring hence aperture will always be set to the smallest that's why it's always dark. Get an old and cheap Nikon 50mm f/1.8 film lens to do the job or bombard the subject with a flood of stadium lights to get enough light through that small hole!