This "intelligent zooming" is mostly just due to 41 megapixels.
The iPhone 4S/5 could "intelligently" zoom to 1.45-1.50x without decreasing resolution (by making dynamic use of the sensor). Unfortunately, at least with the stock Camera app, this isn't the case.
Interestingly, AVCaptureDevice.formats lists zoom levels with "oversampling", hinting on that they, some time, may implement intelligent zoom a'la Nokia 808. Now it's, unfortunately, not the case.
BTW, here's the AVCaptureDevice.formats list for the iPhone5 (this property has been introduced in iOS7; it was private before):
'420v' 192x 144, { 1- 30 fps}, fov:56.700, binned, max zoom:76.50 (upscales @8.50)> - 0
'vide'/'420f' 192x 144, { 1- 30 fps}, fov:56.700, binned, max zoom:76.50 (upscales @8.50)> - 1
'vide'/'420v' 352x 288, { 1- 30 fps}, fov:51.975, binned, max zoom:76.50 (upscales @4.25)> - 2
'vide'/'420f' 352x 288, { 1- 30 fps}, fov:51.975, binned, max zoom:76.50 (upscales @4.25)> - 3
'vide'/'420v' 480x 360, { 1- 30 fps}, fov:56.700, binned, max zoom:76.50 (upscales @3.40)> - 4
'vide'/'420f' 480x 360, { 1- 30 fps}, fov:56.700, binned, max zoom:76.50 (upscales @3.40)> - 5
'vide'/'420v' 640x 480, { 1- 30 fps}, fov:56.700, binned, max zoom:76.50 (upscales @2.55)> - 6
'vide'/'420f' 640x 480, { 1- 30 fps}, fov:56.700, binned, max zoom:76.50 (upscales @2.55)> - 7
'vide'/'420v' 960x 540, { 1- 30 fps}, fov:53.890, supports vis, max zoom:108.00 (upscales @2.91)> - 8
'vide'/'420f' 960x 540, { 1- 30 fps}, fov:53.890, supports vis, max zoom:108.00 (upscales @2.91)> - 9
'vide'/'420v' 1280x 720, { 1- 30 fps}, fov:53.890, supports vis, max zoom:108.00 (upscales @2.18)> - 10
'vide'/'420f' 1280x 720, { 1- 30 fps}, fov:53.890, supports vis, max zoom:108.00 (upscales @2.18)> - 11
'vide'/'420v' 1280x 720, { 1- 60 fps}, fov:51.940, binned, supports vis, max zoom:51.75 (upscales @1.05)> - 12
'vide'/'420f' 1280x 720, { 1- 60 fps}, fov:51.940, binned, supports vis, max zoom:51.75 (upscales @1.05)> - 13
'vide'/'420v' 1920x1080, { 1- 30 fps}, fov:53.890, supports vis, max zoom:108.00 (upscales @1.45)> - 14
'vide'/'420f' 1920x1080, { 1- 30 fps}, fov:53.890, supports vis, max zoom:108.00 (upscales @1.45)> - 15
'vide'/'420v' 2592x1936, { 1- 20 fps}, fov:56.700, max zoom:153.00 (upscales @1.26)> - 16
'vide'/'420f' 2592x1936, { 1- 20 fps}, fov:56.700, max zoom:153.00 (upscales @1.26)> - 17
'vide'/'420v' 3264x2448, { 1- 20 fps}, fov:56.700, max zoom:153.00 (upscales @1.00)> - 18
'vide'/'420f' 3264x2448, { 1- 20 fps}, fov:56.700, max zoom:153.00 (upscales @1.00)> - 19