iPhone’s Regular Digital Zoom, as all Digital Zooms, is kinda B.S., But there is an optical solution, and Optical is always better then Digital!!
@TatWza

Eye Scope for iPhone 4 Got You Covered
Basically the Eye Scope is a case for your iPhone that has a adaptor on board for screwing on the 8x magnifying lens.
Fresh in the Box you get a mini tripod and a bracket for attaching your phone if you want to do some more professional shooting sessions, but you’ll also just be able to slip the lens in your pocket, keep the case on your phone and screw it on when you’re out and about and you see something out the way that you want “Scope out” Perfect for “Check the Pic”

See this Before On the iPhone:

And After On The iPhone:

Clean!!!

Check the full Gallery