Nikon reverse ring - trouble getting an image?

I just got a 67mm reverse ring for my AF-S Nikkor 18-105 (stock lens for D90). When i put the ring on my lens, and put it onto the camera, the aperture says F-- on the screen - this makes sense since there is no aperture ring. however - when looking through the viewfinder, there is almost no light. everything looks black until just at the focal length, and at that point everything is still almost black. When i take a picture, the image is completely black. even at as long as 1" shutter speed. is there any way to change up the aperture? also, how can i get more light into the image?