New Camera and New I-Pad4

Why do photo's imported from my new Sony HX30V not fill up the entire screen of my ipad4? I'm not very savvy with either device! On my first attempt to import photo's using the Lightning to USB camera adapter, it worked beautifully and they filled the entire screen. I have not changed any settings on the camera, yet on the second attempt I am left with a black strip at both top and bottom of the screen. How can I rectify this? Thanks.