A free program for Android, by SmartekSG.

Magnifier Pro – Magnifying Glass is an amazing utility that can turn your phone into a powerful magnifier. It allows you to enlarge objects and text by a lot. It can also work as an excellent magnifying glass for more complex tasks.

To start using this tool, you only need to open the app and point your camera towards the object you want to enlarge. You will see a magnifying glass appear on your screen. Just adjust the zoom level as you see fit and that’s it! You can now use this tool as an excellent magnifier for reading, viewing, and even for working in dim lit places.