When Sony first introduced its concept for a lens camera, it seemed like an interesting solution to the problem of declining compact camera sales. It looks like a giant add-on lens for your smartphone, but it's actually a complete camera. The only role your smartphone plays is as an interface for controlling the camera, viewing your photos and, of course, sharing them via social media if you like. At the time Sony introduced the QX10, which had a sensor of a similar size to a standard compact camera, and the QX1, which featured the same one-inch sensor as in the RX1 premium compact camera. We can assume that the concept has proved reasonably successful for Sony, as it has now introduced two further models. The QX30 has a 30x optical zoom, as well as a sensor the size of that in a compact camera. The other new model, the Sony QX1, features a larger, APS-C sized sensor and interchangeable lenses. Sensor size explained The QX30's sensor is a 20.4 million pixel, 1/2.3 inch CMOS device. That 30x optical zoom gives an equivalent 35mm focal length of 24-750mm, which gives your smartphone (or tablet) much more flexibility than its built-in single focal length device. Also featured is a Bionz X processor, the same chip as found in the company's top of the line cameras, including the A7 full-frame compact system camera. This should mean that it has fast processing speeds and is capable of producing low-noise images in low-light shooting scenarios, though small sensors like this are more noisy in the first place.