To all who responded, thanx!

I own a Nikon D5100 and was wondering, when in Spot Metering, one of the lights showing where the camera is sampling from lights up. How do I select where it should be sampeled from? I've looked in the Owners Manual and can't find it! :?

Yesterday for the first time I heard the expression "Against the light." Can someone explain what that means? I may be a simplton but for the life of me I just can't grasp what it is. Would someone explain it in a manner I can understand?

I'm going to be getting a new lens but I'm worried weather it will work with my camera. I have a Nikon D5100 and was wondering if a Nikon 85mm f/1.8D AF Nikkor Lens, or a Tamron AF 18-270mm f/3.5-6.3 Di II VC LD Aspherical IF Macro Zoom Lens with Built in Motor for Nikon DSLR Cameras
would work?

I understand that I need to experiment to learn what the camera will and won't do. The problem I have right now is I can't take any pictures. If I put any extension tube between the camera body and lens I get an error message that tells me the lens is not connected to the camera. I'm trying to fix that problem, so I can take pictures.

My problem is when I connect thr extension tubes to the camera, then the 18 - 55MM lens, then the macro lens the camera doesn't snap a picture. It gives me the error message that there isn't a lens on the camera. When I try the camera, the 18-55 lens, the macro lens, I can't get focused on my subject. How do I use the extension tubes?
I know this seems like a dumb question but I can't seem to figure it out. Once I do then I'll take hundreds of pictures.

I own a Nikon D5100 and want to get into Macro Photography so I went online and bought a macro lens. Then I read that I should have extension tubes also so I bought them. I now have all this stuff and have no idea how to use them. I need help!!