Why are my Core Prime photos always blurred?

[AC Question]

I'm using the stock camera program that came on my Core Prime. I line up the shot, tap the screen to pick the focus point, and watch the image grow sharp as it focuses on that point. Then, a split second later, it defocuses again. If I'm lucky, and hit the shutter just as it finishes focusing, the photo will be okay. More likely, it blurs itself again and the photo is blurry. This is very frustrating. If I just try to let the camera pick a focus point, it never does, either- the photo is always blurry in that case. What's going on, or what am I doing wrong?

 

[Rukbat]

If the object is within the focal range, it could be a bad camera module.