curves is a tool that allows you to compensate for the dynamic ranges within the image.. you should look into a few books and go to radiantvista.com for some detailed discussion on photo editing.. you have a nice camera - but taking the pictures is only 10% of the puzzle. With digital, you have some much latitude and ability to produce better shots.. you owe it to yourself to learn how. By the way.. you should try using RAW... it would have been simple to fix the above photos in RAW. good luck!