Start your Android camera from the lock screen with Snapshot
This app can open your camera app from the lock screen if you hold the device in landscape orientation and press the power button.
When you're at an event and want to take a lot of photos, you may miss some while you're unlocking your Android and then opening the camera app. And then the moment is gone.
Some phones offer a camera widget for the lock screen, but for those that don't, there's the Snapshot app. Similar to the wrist-flicking gesture on the Moto X to take photos, Snapshot only requires you to hold your phone in the landscape photo orientation and then press the power button. The camera will open and you're ready to take the shot.
Note: This app is made to work with minimal lock screen security, like swipe. While using a lock screen with more security is likely preferred, during certain special events, you may make an exception to allow you to capture photos you'd miss by trying to unlock your device in a hurry.
Step 2: Open the app and tap the slider button to enable its functionality. You may also want to turn off the Status Bar Notification icon, and enable Autostart so you don't have to remember to open the app after a reboot.
If you have more than one camera app installed on your device, you will need to pick which one you want to use as the default. To ensure that this pop-up doesn't ask you to pick a camera when you're trying to take a quick photo, make sure to follow Step 3.
Step 3: Turn off your Android's screen, then hold the device in landscape mode and press the power button. The camera will start and be ready to take a photo!
After your event, you can go back to using a higher level of security on your lock screen, and you can disable the app until you need it again.