The Vivo V5 Plus comes with a Bokeh effect mode, which allows you to control the amount of blurriness of the background. This uses the the secondary camera for depth of field information to recreate and simulate the effect of an aperture ranging from f/0.95 to f/16 using software. The end results are quite astonishing as you can see in various websites. It's not perfect though, some reviewers like Varun Sharma from indianexpress.com, reported that it doesn't work perfectly and when he took a portrait photo of himself, the edges of his glasses would appears blurry, while his face was in focus. There are also some really nice photos on gog.in which show this blurry effect in its full glory, and it looks awesome.
You need to keep in mind that there is a mathematical algorithm involved in producing this smooth bokeh effect. It isn't done only on the hardware side alone because the front camera uses a fixed aperture of f/2.0, an it's definitely not a variable aperture lens.
That being said, the results seems to be quite consistent overall and many reviewers who reviewed the vivo V5 Plus selfie camera and this bokeh mode haven't complained about it and their selfie close-up shots turned out to be really impressive to be completely honest.
On the camera app you'll get a mode called 'BOKEH', just above (portrait mode) or right side (landscape mode) the HDR one. Once you enable it, there will be a slider at the right side of the focus area box which you can drag to change the aperture f-number. You can even see the aperture size changing in a semi-transparent icon in the middle of the focus area box when dragging the slider up and down to change the aperture value. Above the focus area section, you also get to see the f-number being simulated to produce the shallow DOF effect. By the way, you can also apply the blur effect after the picture has been taken by choosing the area of focus and applying the simulated aperture for that particular focus point.
So for example, if you shot a close-up of yourself and there was a person behind you which appeared blurry. You can go back to that photo, tapping on his face to put him into focus and adjust the slider so you become out of focus and he becomes in focus. So when I say background, it also means the subjects in the foreground. There is a great videos by HungryGeeks Philippines that demonstrate how this features works on the Vivo V5 Plus, so take a look! (go to minutes 2:00 to see how it works in practice)
Now, the higher the f-number (e.g. F8.0, 8.0 is the f-number), the less prominent the blurriness of the background will be, and the smaller the f-number is, the more blurry it will become. You can control the amount of blurriness by just dragging the slider and thus changing the simulated aperture. The maximum aperture (the lowest f-number) is f/0.95 and you can drag it up to f/16.
An author for gizguide.com reviewed the Vivo V5 plus and analyzed the bokeh mode. He recommended to use f/2.0 as the lowest aperture, because at f/0.95 you can clearly see that the results look artificial. I can certainly understand why, because in areas that are very sharp, it's hard for this algorithm to produce this effect and the blur effect probably overlaps those edgy areas in a non-consistent way and you can tell, if you look up closely, that this is done by software compared to the perfect results that you get if you get the shot with a lens with the equivalent aperture. I think that for most people and especially when sharing the image at low-resolution, it shouldn't be an issue and you can enjoy playing with the lower f-numbers and just use the effect that look best for that particular shot.
The Bokeh mode on the Vivo V5 Plus is great when taking self-portrait shots (selfies) because it helps to blur unimportant and distracting background details from the image and put the subject at the front of the frame. It gives the image more depth, like a 3D effect.
I think it's an amazing feature that many of you will like and found useful. The Bokeh effect is actually one of the reasons why I love shooting with large sensor cameras and fast lenses with my Nikon DSLR camera. I wish it was also available for the rear cameras as well. I think that in time, the algorithms and the technology used to allow this feature will improve. It's great to be able to capture selfie images with this effect because it's really great for portrait shots, and I can understand why Vivo has decided to put the dual-camera on the front and not at the back, because most of the portrait pictures shot with a mobile phones are selfies, at least that what it seems. Considering the huge trend of the selfie, having a dual-camera at the front is certainly the best way to go.