IPhone 5S camera focus

• No, I hate screenprotectors
• Most of them really don't
• There are certainly bad ones, that are hard to apply or peel off easily, I've even had one that would blur the screen
• Only the ones that blur your screen ;-) They have a slightly matte finish so fingerprints won't be as obvious
• Yes, yes, and yes.
• I suggest you just replace them, they're not that expensive
• I believe it is all stupid...

They just make you feel better. The glass on the new iPhone is incredibly difficult to scratch, and even the older ones hardly scratch at all. I suggest you stop caring so much about a little scratch, the device is supposed to be used. You'll hardly notice it if there even ARE tiny scratches.

If you want to protect it, what you really need to worry about is the thing breaking after you drop it, try a protective case instead. :-)

The quality should be exactly the same. They both use the same API, so unless Apple applies some proprietary image algorithm on the picture, the source pixels are identical.

However, when those apps use the "burst" mode, then the quality of course will be decreased because they are in effect decreasing the resolution of the image for faster capture.