Upgrading your phone with a camera grip attachment is one thing. But doll-sized telephoto lenses that you mount on top of the rear camera? C’mon. I wrote the Vivo X300 off as a gimmick, a funny concept designed to generate attention rather than actual sales. But then I spent a weekend carrying the phone and its elaborate kit of goofy little lenses around — and I had way too much fun. The Vivo X300 Ultra is an update to one of the very best phone cameras out there . It’s only available in China