Feature request: The A7R3 allows APS-C mode to be selected by a custom button, seems like a simple firmware upgrade for the A7R2 - can you include, would be VERY useful. Save me digging into the menu every time I want to grab a little extra reach on a lens (I'm more than happy with the MP trade off so I can instantly see the framing and DOF), in fact it's one of the reasons I bought a high MP camera in the first place. Thanks!