One of the best features of the Vivo V5 Plus is its dual lens front camera. One camera is used to capture a 20MP image while the second camera uses a 8MP sensor and captures depth-of-field information. This information can thereafter be used to produce a beautiful bokeh effect that resembles that of a DSLR camera, one with a much larger sensor and a fast lens. The phone uses advanced algorithms to produce this shallow DOF effect and in fact, it allows you to add focus even after the photo has been taken. So you can shoot the image, and on your spare time adjust the blur effect to a particular place in the image.
The main 20MP front camera uses the Sony IMX376 1/2.78" image sensor. This is the same front camera used by the Vivo V5 and the Vivo X9 and X9 Plus, with 5-lens elements (5P) and a fast f/2.0 aperture lens to allow you to get well exposed selfies even when shooting in less optimal lighting conditions, like at night or in a relatively dark indoor place.
A 1/2.78" is still a small sensor, but it's larger than the 1/3" in the iPhone 6 but smaller than the 1/2.5" in the Nokia Lumia 1520 for example. The main issue here is the high resolution of the sensor, which lowered its low-light capabilities. The fast F2.0 aperture lens balances it a bit, but it's still not enough, the pixels are just too small to make the front camera capable of delivering impressive low-light shots. Luckily there is a softlight flash that can help with the illumination of your face when shooting in low-light. By the way, the pixel size of the IMX367 sensor according to wikipedia is 1.0-micron. The sensor produces images at 5120x3840 resolution.
From what I've read on an unofficial websites, this sensor was developed closely with Sony, Also googling the image sensor model didn't yield any results for other phones other than Vivo's that uses it. It likes this sensor was made exclusively for Vivo, at least a timely exclusive, so we might see in in other phones as well in the future.
Don't confused this sensor with the IMX377 one that comes in the HTC 10 has 1.55 micron pixels and it's one of the best performing sensors on the market right now. If you have more information about this sensor, please comment below and share this information with others. Thanks.