If you would like to improve the camera quality of your iPhone 4S, you can easily accomplish this with a supplemental lens such as the 4 in 1 OlloClip iPhone lens.
The OlloClip 4 in 1 photo lens greatly improves image clarity by eliminating lens distortion and you get the ability to capture iPhone photos and video in different ways, thanks to the four in one lens system that includes four lenses into one compact solution.

You get four lenses in one: Fisheye lens, Wide-Angle lens, 15x macro and 10x macro lenses. To access the 15x macro lens and the 10x macro lens you simply unscrew and remove the Wide Angle or Fisheye lens
The Fisheye lens and the Wide-Angle lens screw to the body of the Olloclip which has both macro lenses on either side.
The Olloclip 4 in 1 lens slides on and off the iPhone 4S in seconds so it's always ready whenever you want to get the shot you want.
The Olloclip lens system comes with carry pouch carrying an iPod Touch adapter and two clear lens covers to protect the Olloclip 4 in 1 lens system, as well as the Olloclip app, which gives three deifferent levels of cropping (4%, 8% and 12%)
The 4 in 1 olloclip lens is made from precision ground aircraft grade aluminum and coated glass optics that reduce reflection and glare. Check out the Olloclip iPhone 4s 4-In-1 Photo Lens