Let's start with numbers. The Galaxy J3 (2017) features a 13 megapixel main sensor at the rear with f/1.9 aperture, autofocus and LED flash. At the front, it features a 5 megapixel sensor with f/2.2 aperture and LED flash. This is a fairly standard configuration for a device in this price category.
In practice, the J3 (2017) is quite average. It's not the worst in the price range, but it's not the best. If photoraphy is the main criterion for you, I wouldn't recommend this one. A Moto G4 Plus or a Huawei P8 Lite 2017 have the advantage in this regard.
In terms of quality, when the light conditions are good, the camera on the Galaxy J3 (2017) is doing quite well. There is a lack of detail and the backgrounds are often quite bland. The development is also a bit slow but the reactivity is decent and it is possible to take a series of shots on the fly without any problems. In low light conditions, it is a little more problematic because the Galaxy J3 (2017) sensor is not able to capture enough light. As a result, there is a lot of noise on the shots and pictures are often blurred.
The front camera also gives fairly average results. The shots lack a little sharpness. Beware if you want to use the flash, as it tends to do more harm than good. Finally, on the video side, it is possible to film in Full-HD. The result is good and I find the quality of the videos better than the photos.
Overall, the J3 (2017) is a bit disappointing, camera-wise. But in my tests, it did do better than the 2016 version.
You can get an idea for yourself by looking at our pictures below:
Source : https://www.androidpit.com/samsung-galaxy-j3-2017-review