android - Android camera2 API在AF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 获得焦距值。但是，AF 模式下该属性始终为零。有什么办法可以在AF模式下获得焦距？

Answer 1

Shortest distance from frontmost surface of the lens that can be brought 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

In other way, if you want to manage focus, remember that LENS_INFO_MINIMUM_FOCUS_DISTANCE give you the minimum focus, but to get the "Max" focus you must use 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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For 2021 when using CameraX, here's how to find camera characteristics such as LENS_INFO_MINIMUM_FOCUS_DISTANCE:

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);

Answer 2

如果值为LENS_INFO_MINIMUM_FOCUS_DISTANCE0，则表示为定焦，不支持手动对焦。功能有限 - 存在于所有报告至少HARDWARE_LEVEL_LIMITED