Sony loves big sensors, as do keen photographers. Big sensors have bigger photosites (pixels), and deliver better dynamic range, better performance at high ISO settings and better defocusing effects.
Sony demonstrated this last point with a smartphone and one of its RX100 compact cameras. The smaller sensor in the smartphone uses a smaller lens which renders everything in the scene sharp, at all distances, but the much larger 1-inch sensor in the RX100 uses a larger lens which captures your main subject clearly but defocuses the background.
This defocus capability is all to do with lens apertures, physics and optical science, but the upshot is that bigger-sensor cameras don't just capture sharper pictures, they let you use creative defocusing for more atmospheric, professional-looking pictures.
We got to try this out with the best thing at the show (sorry, Sony), a model train track with tunnels, stations, little figures and even a helicopter. We could have stayed there for hours, but we also had to look at some cameras.
Sony was also keen to big up its A7-series compact system cameras, consisting of the A7 II base model, high-end 42-megapixel A7R II and high-sensitivity A7S II. These have full-frame sensors which are much larger again, and the same size as the old 35mm film negative.
In fact it's often difficult to get across the concept of sensor size and what the differences actually are, but Sony had a rather neat display made up of naked sensor units mounted on a backplate for comparison.
The A7S II is a high-ISO specialist, and Sony demonstrated its image quality and autofocus response with an illuminated fairground scene for the model train track (yes, back to that).
The Sony team closed the show with a quick demo of its HDR-AZ1VR action cam, clamped to a model train truck and pushed round the track at speed by a model steam loco. That was the best bit of all, but we weren't allowed to drive the train. And then we had to leave.