Photographers and people who know about DSLR cameras

I have a nikon d7000 and when i take pictures of people in the sun, when i look through the viewfinder or even have the picture show up on the display screen it looks perfect with the lighting on their face and everything but after i take the picture and look at it their face is really shadowy and the picture is dark. Can someone help me and let me know what I should be changing?

You can't go by how it looks to you since your vision isn't the same as a camera's metering system. The reason for the images being dark is that the meter is compensating for the brightness of the sun. You would be better not shooting into direct sunlight but you may be able to compensate by using a flash rather than boosting the exposure and blowing out the rest of the scene.

You have to take the time to learn about exposure. It's that simple. There are so many ways a camera can be tricked it's a miracle it ever it's it right; Which it rarely does, as you'll quickly pick up on in just a few minutes here. You've seen yourself one of the ways auto mode can fail.

It's a complex subgect but basically you'll learn to control the factors to anticipate and balance the light to make the picture look the way you want it to. You can get it a week if you really study hard. Go to the library and take out every photography book you can. Read about the chemicals and light in the Understanding Exposure; Peterson. And then delve into why you use those chemicals or that light in On Photography; Sontag. And grab anything that piques your interest. The worst that can happen is you bring it back and get a better one.

You need to change your expectations. Cameras have less dynamic range than your eyes do, so your pictures will show less detail in the shadows and highlights than what your eye can see. Therefore, it's important to set your exposure for the subject. If you want to shoot in that sort of lighting, expose for the face, either by manual setting or by using spot metering. The sunlit portions of the scene will be badly overexposed, though if you shoot in RAW you can gain a few more stops of latitude. Another option is to use fill-in flash or reflectors to put some light on the face.

You should be learning about exposure and using manual spot metering off the face.