"allows you to re-focus images after taking them, as well as alter perspective "
Lytro Illum Professional Light Field Camera Review - The Lytro Illum is a new professional Light Field Camera that lets you create "Living pictures" that can be re-focused after shooting.
"At the heart of the Lytro Illum is the Lytro Light Field Sensor that features a micro-lens array made up of thousands of tiny lenses designed to record and measure light from multiple directions. Developed by Ren Ng, founder of Lytro, the Light Field Technology is what allows you to re-focus images after taking them, as well as alter perspective "
"A number of learning videos are provided on the Lytro website to help you get the best from the camera, and in many ways you will need to rethink how you take photographs and what you are taking photographs of. If you mostly take landscape shots where everything is on a single focal plane (all the same distance away from you, or at infinity focus) then you will not see much benefit in using the Lytro Illum. Instead, you would be best using the Lytro Illum for close-ups, portraits, or environmental photos where there are a number of elements in different distances and positions in the photo."
"In playback on the camera, you can change the focus point simply by pressing the area on the screen. Using the camera connected to an iOS device, over Wi-Fi, you can alter the aperture to give a shallow depth of field or have the whole photo in focus, as well as alter the perspective view. "