Android: Android Compatibility and uses-feature

Android is designed to run on devices with different kinds of capabilities; however, some APIs won’t work correctly if a device lacks corresponding hardware or feature. For this case, Android Market provide a mechanism to prevent apps from being visible to devices which don’t have features the apps require.

How Android Market filter apps from devices without required feature?
Android Market check element in your app's manifest.

Example: An app which requires camera
1. Request camera permission

2. Specify camera is required for this app

*note
Any app that requests camera permission but does not declare any camera features with the element will be assumed to use all camera features (auto-focus and flash).
Thus, this app will not be compatible with devices that do not support all camera features.

ref:
1. Android Compatibility
2. uses-feature