If you're new to DSLR photography or just looking to brush up on your skills then you should take a look at CameraSim for the iPad. The app is a camera simulation that lets you focus on a subject and change common camera settings like shutter speed and aperture to see how each one influences the final picture.
CameraSim launches with a clean UI that has sliders for eight camera settings. In the center of the screen is a sample subject of a girl with a pinwheel at a playground. You can tweak the settings like the lighting, ISO, focal length and more. When you are done, you just press the "snap photo" button to take the picture. The iPad app will then show your resulting shot and offer encouragement if the photo was good or
