Android camera2 API 在自动对焦模式下获取焦距

Question

我正在使用 Android camera2 API。

我可以在手动对焦模式下使用 LENS_FOCUS_DISTANCE 获取焦距值。但是，该属性在 AF 模式下始终为零。 AF模式下有什么方法可以获取焦距吗？

Answer 1

Shortest distance from frontmost surface of the lens that can bebrought into sharp focus.

If the lens is fixed-focus, this will be 0.

http://developer.android.com/intl/es/reference/android/hardware/camera2/CameraCharacteristics.html

换句话说，如果您想管理焦点，请记住 LENS_INFO_MINIMUM_FOCUS_DISTANCE 为您提供最小焦点，但要获得“最大”焦点，您必须使用 LENS_INFO_HYPERFOCAL_DISTANCE。

float yourMinFocus = mCameraCharacteristics.get(CameraCharacteristics.LENS_INFO_MINIMUM_FOCUS_DISTANCE);
float yourMaxFocus = mCameraCharacteristics.get(CameraCharacteristics.LENS_INFO_HYPERFOCAL_DISTANCE);

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对于 2021 年使用 CameraX 时，以下是查找相机特征(例如 LENS_INFO_MINIMUM_FOCUS_DISTANCE)的方法:

theCamera = cameraProvider.bindToLifecycle(...
CameraCharacteristics camChars = Camera2CameraInfo
   .extractCameraCharacteristics(theCamera.getCameraInfo());
float discoveredMinFocusDistance = camChars
   .get(CameraCharacteristics.LENS_INFO_MINIMUM_FOCUS_DISTANCE);
Log.i("dev", "min focus is " + discoveredMinFocusDistance);