Out of Weibo, we have these photos of Oppo's rumored NFC camera attachment posing on the back of an Oppo Find 7. What we're looking at is a lens with 10x optical zoom that doesn't attach in front of the phone's camera lens, but is fixed to its back and beams photographs to it through NFC or Wi-Fi. It's not yet clear whether the attachment works with other phones, although there's nothing in these photos to assert the opposite. The module also has dedicated power and an illuminated on and off key, which further suggests the ability to operate independently.
Detachable lens for smartphones are a pretty niche accessory, with Sony and Scheider Optics' iPro Lens's products being the biggest of the few competitors in this sector. Other vendors, such as Samsung, prefer to release entire cameraphones, such as the upcoming Galaxy K.
Hopefully Oppo will price its lens sensibly, although there's no way it will come cheap.