Sony and a number of other vendors showed so-called 4K TVs. The name comes from their horizontal resolution of almost 4,000 pixels: they have a resolution of 3,840 by 2,160 pixels, four times the number of pixels found on HDTVs, which have a resolution of 1920 by 1080 pixels.

It is easy to get carried away when seeing a 4K demo: Sony's set produces a 2D image that, thanks to the higher resolution, feels almost as immersive as a 3D image.

But demonstrations at trade shows such as IFA hardly give a balanced view of how a product performs under normal circumstances. All the 4K demos, not just Sony's, used slow-moving, bright images, which are the least challenging to reproduce.

While it is easy to be impressed by the images, it is also easy to see why 4K TV sets will initially have an uphill battle for a place in the market.