Lock zoom

Lock zoom allows you to "fix" the zoom at a certain level, and maintain it when you move to the next pages.

First, you need to enable it. Go to Reader settings -> gestures and zoom -> Lock zoom.

Once enable it, after you zoom in a page, you will see the following banner appear at the bottom of the screen for a few seconds:

Tapping on "Lock Zoom" will lock that zoom level. If you need to remove that lock, simply zoom out or change the zoom level.