You cant compare the camera quality from the iPhone 4s with the one s because of screen resolution and size. The iPhones has a small screen with high resolution and higher pixels per inch with a 3.5 inch screen. So taking a pic with the iPhone and looking at the pic from the iPhones screen, quality is going to look much better but doesn't mean it is.
Take a pic with the iphone, send it to your one s and look at the pic you took with the iPhone through the one s screen. The pic won't even load full size, they will load super tiny. And if you try to blow them up, they will get distorted. Even when my cousin and my friend that own an iPhone 4 send me pics, I always receive them really small, every single time.
There's no way the Iphones camera quality should be even close to the one s camera quality. One s should be 10x better.