Please Help!!!

Well, today I finally got to try out my new Pentax K100d super DSLR. When I use the camera in auto mode I was getting some fine, well detailed shots. However,when I put the camera in Av mode to change the aperture and add some DOF my pictures take on a shade of blue. It literally looks like I am taking a picture through a piece of blue glass. Also, for the record I am not using autofocus lenses. I am using some older pentax lenses that work for my camera.

Any help will be greatly appreciated!
Thanks

 

There wouldn't happen to be a filter attached to that old lens would there?

 

^There is a filter but it's just a UV filter to protect the lens.

 

I know when I forget to take my uv off when indoors, my pic's are blue.

 

Did you change the white balance to incandescent recently?

 

^That was it, thanks!
Now I really feel stupid!

 

Don't feel stupid I spent 4 hours last week trying to figure out what was wrong. not once even thinking about WB. with a new cam everything can get a little overwhelming sometimes.

 

I make that mistake all the time that is why I suggested it...

 

ahaha yes. That's what I thought of too. Happy Hour was having the same problem a few days ago.
Always something simple.