Why is my back camera blurry and I don't know how to fix it?

I have a Nokia Lumia 925 phone and my back camera always seem to get blurry. I don't know how to "focus" it and I tried restarting my phone to see if it will go back to normal. It hasn't work and I also tried cleaning the lenses. It was still blurry and I don't know what to do to make it clear again. Someone please help?

Read more: Why is my back camera blurry and I don't know how to fix it?