Q: Iphone 5s isight camera

IVe noticed that my iphone 5s front camera is foggish? Its not as clear as my friend's.

sometimes it doesnt seem like an iphone camera at all, especially in a bad lighting.

but with the natural lighting, it looks fine, but in a place with low light it looks really bad (foggish)

im wanna know;

1. Is the camera installed in my phone is a fake one?

2. Is my lens dirty from the inside? I dont see any debris at all, but maybe it's foggish inside?

i'm so annoyed with the quality, it doesnt seem like an iphone camera