I think one of the main highlights if the Galaxy J7 Pro is its 13MP F1.7 aperture rear camera. If we look at the other J7 models, we can see that the J7 Prime that was launched on October 2016, comes with a 13MP F1.9 aperture lens and the J7 that was launched on May 2016, comes with a 13MP F1.9 lens as well.
This means that Samsung aimed to make sure that the J7 Pro can take even better photos and videos when shooting under low light conditions. Of course the lens aperture isn't the only factor that affects the image quality when shooting in low light conditions, but as we've seen in many reviews, it is one of the main factors. The reason is simple: to get better quality image and to be able to shoot well exposed images in low light, we need more light.
By the way, the Samsung Galaxy J7 Max (2017) also comes with the same camera setup, a front F1.9 aperture lens and a rear f/1.7 lens. In general, I am happy to see that Samsung is pushing the aperture numbers down on its less expensive phone so more users can enjoy the ability to capture good quality images and videos with less creative limitations. I know how frustrating it is being limited to taking photos only in good lighting conditions and seeing people with iPhone 7 or Galaxy S8 taking stunning night shots. Of course if you want the best of mobile photography, you'll need to pay extra for it. The thing is that I just wish that Samsung would release model that focus mainly on camera quality. So users can enjoy flagship camera performance, and reduce the overall performance and remove features that aren't necessary for getting good quality images.
This is a personal fantasy of mine, but as I said, Samsung is doing what it can under the price restrictions, to make sure you ALSO going to get a camera that can perform well in low-light. If I was Samsung, I would have released a camera with a sensor with much larger pixel, like what HTC did with its UlraPixel technology instead of going with a 13MP sensor with much smaller pixels. Hey, I don't even mind 3MP with mind blowing image quality and low-light performance, I care less about details because I usually just share my photos online with friends. Maybe such a phone will come some day.
Another benefit of a faster aperture lens is that you can achieve a shallower depth of field effect. However, due to the sensor size, which is very small, this effect is not that prominent, unless you are shooting macro. I've tested this on the Oppo F3 Plus which also has a rear camera with a f1.7 lens and the out-of-focus effect is really not that significant. This is the reason why many of the higher-end smartphones feature a simulated shallow depth of field effect, and this works amazingly well. So if you really love that background blur Bokeh effect, you probably better off with a phone that can digitally simulate it, rather than relying on a fast aperture lens to deliver these results
There are also plenty of low-light camera samples taken with the Galaxy J7 Pro rear camera. Take a look at these low light test shots on gizguide.com website. You can see that the exposure, clarity and level of details are really impressive. Of it can't match the a flagship camera performance, but no doubt that the fast aperture is doing an excellent job in helping maintaining the details in those low-light shots. This is exactly what I was expecting from the J7 Pro, a satisfactory low-light performance. Give this camera just a bit of good light source, and it can perform really well.
So if you are searching for an affordable phone with camera that features a fast aperture (in this case, an f/1.7 one), I think that the Galaxy J7 Pro will fit your bill. The phone cost 17,900 Indian Rupees (~$280 US Dollar), so a fast f/1.7 lens is definitely a good offering. Not so far back we only saw this type of fast aperture lens on flagship smartphones. As you can see, in 2017, and I'm sure this trend will continue, we get to have this bright aperture lens on entry-level smartphones as well.