So I am reading Understanding Exposure, and I have been trying to understand metering. I have a D3000, and I am trying to understand how you meter for other objects than the one you are interested in photographing (blue skies, etc.) I am reading the manual for my camera, and I am still fuzzy on a few things. Id guess if I am metering for a blue sky, I would set my meter to spot, meter for the sky, press the AE-L (Autoexposure lock) button, then go back to the original object intended for the picture? Question is, in order to focus with AE-L pressed down, you have to focus before you press the button. So at what point to I press the shutter button to focus the camera?