android: device not supported by app- why?

Thanks to Entreco I found the answer. Just looked up the supported devices in my app settings. Then, by comparing the feature specifications of the not supported tablet (Acer Iconia A200) to a supported device (A510 tablet) I found the answer: The A200 does not have a rear camera. So what's def. missing is following entry in the manifest:

<uses-feature android:name="android.hardware.camera.front" android:required="false" />

Ok, this is a long shot, but could it be the camera is disabled for some reason on that particular device?

It seems that the following permission:

<uses-permission android:name="android.permission.CAMERA" />

Implies that your app is using android.hardware.camera and android.hardware.camera.autofocus features. However you defined only android.hardware.camera.autofocus as non-mandatory. So try adding:

<uses-feature android:name="android.hardware.camera" android:required="false" />

Details about google play application filtering

Add this to your manifest:

<supports-screens android:smallScreens="true"
              android:normalScreens="true"
              android:largeScreens="true"
              android:xlargeScreens="true" />

I'm assumuing that leaving out explicit support for tablets (xlargeScreens) causes Google Play to consider it unsupported.