I was wandering if it could be possible to implement in an application, that has to display for example an image, a kind of zoom like the one depicted in the flash below.
You need 3 fingers to use this zooming mode… (assuming you’re using your right hand…

I is for Index finger
M is for middle finger
R is for ring finger

a ipothetical use could be described like this:

1) you put your Middle finger on the iPhone, dragging (not showed) let you pan the image.

2) when you want to zoom in you have to put your Index finger on the iPhone and hold. you have continuous zooming.

3) if you release your Index finger zooming stops.

4) to zoom out you can put your Ring finger on the iPhone and hold. you have continuous zoom out.

I think that panning while holding down your Index or Ring finger could be possible…