The dual-camera craze is real at Mobile World Congress, but Oppo decided to break from the pack with its own, very clever implementation. Long story short: the company managed to build a 5x "lossless" zoom system for smartphones using two sensors and a zoom mechanism inspired by periscopes. The latter part is nothing new, of course: 'tis a feature which was once common on compact digital cameras, and ASUS even applied this to its ZenFone Zoom last year. Oppo's implementation, however, takes things up a notch.