[rfatnabayeff]

When they zoom in using the touchscreen - isn't that the digital zoom, not optical? If so, the last x10 seems not legit.

[LionRoar]

Indeed! I was going to remark the same. Also a side effect of digital zoom is that it is not perfectly sharp. You see this already in the example pictures. After all, digital zoom is more of an effect then real zooming. For this reason I never use digital zoom on a digital camera. On my PC I have software that does a better job :)

[evacuationdrill]

". . . the iPhone 4S is equipped with a 5x digital zoom, not optical zoom." http://www.imore.com/iphone-4s-8mp-camera-hands

Other sources I looked at said that some phones do have optical, but it's generally tough due to the depth needed.