So Google basically took what Lytro has been using hardware to achieve, and did it entirely in software. Pretty impressive.
It'd be fun to play around with the software to see in which cases it breaks (perhaps taking a photo of a framed landscape photo with another landscape behind, for example)
Instead of capturing the 'light field' you may as well capture most of the image.
Secondly the loss of the 2nd derivative of the k-vector makes lightfield currently unsuitable for use in a microscope (although they are working on it...). Although there might be better techniques for refocusing, such as division in the spatial frequency domain.
see http://www.cnet.com.au/nokia-vs-lytro-the-refocusing-challen...