I sent a feedback to Samsung via this app (Samsung Members), and you can do as well so they may notice that we all have this issue:
My S7's front camera seems to focus the background more rather than the people in the picture. Details of the faces and nearby objects are blurred while the background and far objects are clear and sharp. The Facebook Messenger camera app does not do this. Could it be a software issue of Samsung's camera app? I have read a lot of S7 users that are unhappy with the output quality of the S7's front camera, one even commented that the S4's front camera is better. Hope you can address this problem the soonest with an update on the camera app. Thanks!