Now, Sony is poised to upend the camera industry with the new Alpha A7 and A7R mirrorless cameras. The A7s are the most advanced and expensive mirrorless cameras Sony has ever produced. They may look similar to the company’s line of NEX cameras, but the A7s have one significant difference: a *much* larger image sensor. Sony’s earlier fixed-lens RX1 shifted this notion a bit: it’s a remarkably small camera with a great big sensor stuffed inside.