Touch ID weird action

[Jentek]

On my Touch ID enabled devices, a light double tap (not pressing though) on the Home button drops the display by half the screen, another double tap brings it back!

What is it for?

 

[DaveWT]

It is intended for the bigger iPhones (6s, 6S Plus) so that you can reach the stuff on the upper half with your thumb. It saves you having to reposition your hand from where you are holding it lower down in order to reach the things at the top.

 

[Jentek]

I have the 6S, if I can reach the home with my thumb to double tap then I can reach the top too!

Probably designed for those driving and using the phone with one hand !

 

[DaveWT]

Then you must have a very long thumb and fingers. My wife's 6s isn't handy right now to try this but if I am holding my 5th generation iPod Touch (which is a bit smaller) in one hand near the bottom (i.e. hand cradling the Touch) so I can flex my thumb to reach the home button, then I can't reach the top of the screen without shifting my hand position.

Sure if you hold the 6s (or worse, 6s Plus) in one hand and use the other hand to access the screen, there is no problem but this feature is for one handed users (whether driving or not.)

 

[chas_m]

It is intended for the bigger iPhones (6s, 6S Plus) so that you can reach the stuff on the upper half with your thumb. It saves you having to reposition your hand from where you are holding it lower down in order to reach the things at the top.

You're right that its a feature designed to make one-handed operation of the larger iPhones (6/6s/6 Plus/6s Plus) possible for those times when you don't have a second hand free (like anyone with a baby, for example).