Okay, don't know enough about samsung telephones to tell you how to fix it but heres the issue (very very boiled down and in a second language, haha). The depth of field is indecated by the F-stop. The higher the F value, the more is in focus. Meaning that things in the foreground and background can be both in focus, to a certain extend of course. But here's the issue: in doing so less light can come into the sensor meaning picture will become very dark. A simple way to negate this effect is buy lowering the shutterspeed. Meaning the sensor will be exposed longer to the light, therefore creating a better lit picture while still maintaining a high enough F-stop.
Now, here's the phone's issue. Phone camera's usually do all this automatic. So three practical tips:
1. Try to google if you can manually set your F-stop on your phone.
2. Use a very brightly lit room. Your phone will most likely do two things. One raise the F-stop and two use a higher shutterspeed. Hopefully, more will come into focus.
3. By tapping the screen you can usually decide what your phone focusses on. Try not to focus on the closest model but one in the middle. If the Fstop is high enough it should help.
Hope this helps.
edit: depending on you camera it might have a portrait/landscape/sport/etc setting. Try to use landscape instead of portrait or sport. The first will lower your f-stop to create a smooth picture and the second will try to get the fastest shutterspeed to catch movement. Both won't help your issue. If you take a picture of single model a low F-stop (portraid mode) will usually improve the picture.