You've no doubt seen those apps that allow you to use your rear-facing camera's flash as a flashlight. However, one thing you've undoubtedly never seen is an app that allows you to fine tune its brightness and control exactly how much light is emitted. This is exactly what XDA Forum Member MohammadAG has done with his latest application Adjustable Torch.

Adjustable Torch is verified compatible with the Galaxy S 4 and Galaxy Note II, but it should be compatible with any phone that uses the file /sys/class/camera/flash/rear_flash. Even better than the app's functionality itself, however, is how MohammadAG's spirit of sharing. He has made his application open source under GPLv3 license so that other developers can learn from his app and incorporate similar functionality in their own apps.

If you wish to give this a try on your own device, head over to the application thread. And if you wish to see how MohammadAG did his magic, or if you wish to incorporate similar functionality into your own app, head over to his Github. Be sure to leave feedback in the thread after trying the app if you have a previously unsupported device.