iOS low light filter
Those of us who hunt at night understand the long hours spent in the blind waiting for that big feral hog to walk in. I have always been annoyed at how bright the phone back light is even at the lowest setting. Whenever I go to check my phone it seems like the entire blind lights up like the Clark Griswold's home on Christmas. Year's ago I discovered that for iOS devices there is a "zoom" filter that can be used to reduce the brightness of the screen even further. This helps a lot with keeping light down in the blind and also keeping my eyes better adapted to the darkness.
The first step is to go to: Settings -> General -> Accessibility
Under the "Vision" menu choose "Zoom".
Scroll down to "Zoom Region" and select "Full Screen Zoom". Next, back out of "Zoom Region" and now select "Zoom Filter". Choose "Low Light".
Return to the top of the zoom menu and turn on "Zoom". The switch will move to the right and turn green.
It may zoom into the screen initially and so now you will have to make the phone zoom back out. In order to do this you will tap three times quickly (triple tap) on the phone screen using three fingers. The zoom menu will appear and you can change the magnification back to the lowest setting.
Triple tap with three fingers again to get back out of the zoom menu.
There you have it. Now whenever you want to enable the low light filter, just to the General -> Accessibility -> Zoom and enable "Zoom". When you want to turn it off, return to that menu and disable "Zoom"
To get the lowest brightness setting you will still need to dim the back light. To do this swipe up while on the home screen to bring up the shortcut menu. Move the slider down to the lowest setting.
One additional "hack". If you go to General -> Accessibility and scroll down to "Accessibility Shortcut".
Enable the shortcut for zoom. Just select "zoom" in the list. In the case of iPhone devices with the home button, this enables you to just triple tap the home button to enable and triple tap the home button again disable the low light filter rather than navigating to the zoom menu.