Camu is the smallest camera application for Android that exists, but in addition, the camera image is a very fast, even on slower devices. Say, for SGS2 image for 1 second with all the flash, while usually takes about 4-5 seconds. But that's not all, the application has live filters and record video. It's very lightweight and simple design. There has too many options and is ideal for imaging and recording.
2) Focal - free
This is an open source camera, which was the center of attention when it first appeared, but now less story about it because it is not more than a year ago updated. However, I decided to put it on the list because it has a lot of options, a free, lightweight, has a nice user interface, effects, sounds ... It is also a bit faster than the default application images on slower devices.
This application images up to 30 frames per second! So you can take a picture of a moment 30 times and later select the best image. Also, the application provides a tool for creating animated GIF.
4) Camera51 - free
If you can not determine the perfect frame, the application will assist you. Just to pick up to 3 objects for which you want to be in focus, and the app will show you how to position the camera for the perfect shot. The application detects objects, faces, lines and the result you get the perfect frame that will include all relevant objects and subjects appear.
It is not free but is worth mentioning because it is really great. The name tells her to use it to manually adjust all Shutter Speed, Focus Distance, ISO, White Balance, Exposure Compensation ... and this application has increased the speed of painting. But only works on Android 5.0+ and requires Camera2 API, so that a very small number of devices supported.