If your phone has a wide-angle lens, you should see a 0.5 zoom factor option. Click on it to activate the wide-angle feature within the app.
On Android, if you have the HDR option activated, you will not be able to access any zoom factor option besides 1x.
If you are using Android, it is possible (due to system limitations) that your device does not let our application access the wide-angle function of your camera. If you believe this is the case, feel free to contact us and let us know the details of which phone model and OS version you use. Rest assured that our developers are working hard to solve this issue, and we will get back to you as soon as we will have this fixed.