My Nikon D90

So I purchased a new camera a few days ago, the Nikon D90.

This beautiful state of the art memory maker is more camera than I know what to do with. I have never taken a photography course and don't know my aperture from my shutter speed. There are so many menus and options that I fear I may turn it to "auto" and leave it there. I do feel confident though, that I will take excellent pictures with it, and it will be a learning curve for me to slowly go through all the components of what this high tech machine can do. I am excited to learn all about each setting and what I can do with it. I want to take beautiful pictures of my children, photos of items so close up that you can't tell what they are (even though they are perfectly in focus). I want to know this camera inside and out! The Nikon manual and I are going to have a special relationship. And I know that I paid too much money for this camera for it to end up a point and shoot, because if that's what I wanted, I would have kept going with my Canon digital elph.

My only problem so far is shadows. In the past two days, I have clicked off over 100 pictures of random things around my house, plants, my dog, my kids, the furniture even. And on the odd picture, I have a half moon shaped shadow at the bottom of my picture, dead center at the bottom of the frame.

(My sad three year old illustrates my shadow problem.)

And only on indoor shots with the flash on, with the lens at the shortest setting, not zoomed out at all. And I have checked the obvious - is my finger over the flash, is my finger or part of my hand over the end of the lens, is my camera strap swinging into view...but no.

(Our husky/collie/heinz 57 dog Keiko also illustrates the shadow problem). These photos are all taken at different times of the day.

(My three year old, happier this time to illustrate the shadow. He's all dressed up to play in the snow for the first time this year!) The pictures are also taken in different areas of the house.

(My sleeping daughter is willing to help display the shadow too). These shots are at different angles as well.

She is disgusted with my photography skills and can't even look at me!! In general I am getting wonderful pictures so far, except for this little tiny glitch.

Anyone out there know why this super costly piece of photo equipment is leaving shadows at the bottom of my pictures??? I will be taking the camera in to the photo shop where I purchased it tomorrow, to find out if this is user error or if this camera was slammed to the ground in the box causing some defect!! I'm hoping it's something I've done, as I am so excited about this camera that I really don't want it to be something I can't fix. I will be extremely disappointed if this is the case.