Shift has a lot of potential due to its unique selling point - the ability to create your own photo filters, which you can save and apply to any picture you take.

It's a lot simpler than it sounds: tap the button to chose from one of a number of pre-set filters, then dial the intensity up or down, or drag on-screen dots to reposition its effects.

While the choice of filters is limited at the moment (many look similar) and more filter editing options are needed, Shift is an app with a bright future.