[panrafal]

There is an app for iOS - seene.co. The amount of movements you have to do to capture enough pixels is prohibitive for my taste. I think that google has nailed it - it's super simple.

As for storing the layers - you would only have the "from above" pixels, and only a few. Probably that's why there is only a LensBlur in their app in the first place.

If you just want a small displacement effect like on depthy - then the key is no sharp edges in the depthmap. We will try to tackle this in one of the upcoming updates...