Picture this.

You're at a party or some event such as a hike in a beautiful spot. You're using your iPhone to take pictures, but you don't want to walk around with it in your hand all the time. But you also want to be able to get quick access to the camera to take those awesome shots when they come your way. 

Now, Apple's given iPhone owners quick access to the camera from the lock screen. Press that little camera icon on the front screen and iOS will jump straight to the camera.

Neat!

But it's not really that fast, because you have to get the iPhone in the correct orientation, find the icon, and press it just right to work.

The quick access button for the iPhone's camera on the lockscreen

While this method is great generally, at times when you need faster access to the camera, it just doesn't cut it.

Here's how to make it much faster, implementing the "secret" Apple button on the back of the iPhone.

OK, did you just look for a secret button on the back of your iPhone? Well, while there isn't a physical button, the back of your iPhone is touch-sensitive (actually, it's tap-sensitive), and you can use this to activate features.

Your iPhone can detect double taps and triple taps, and you can assign actions to each of these.

But where is this feature buried?

TapSettings > Accessibility > Touchand scroll down and tap onBack Tap.

Back Tap in iOS Settings app

Here you can assign one of over two dozen actions to carry out for double and triple taps.

Lots of actions to choose from

Just select the actions you want, and then closeSettings.

It takes a little bit of practice to get the taps right, but once you've got them committed to muscle memory, this is a super-fast way to bring up the camera for those quick shots you need.

It works whether your iPhone is locked or unlocked.

This is also a quick way to turn on the flashlight