android - 如何在 Android CameraX 中使用手动对焦？

Question

我正在尝试像在 Camera2 API 中一样对 CameraX 进行手动对焦

在 Camera2 API 中我使用以下代码

final CaptureRequest.Builder captureBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE); 

captureBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_OFF); 

captureBuilder.set(CaptureRequest.LENS_FOCUS_DISTANCE, mLensFocusDistance);

android camera X 可以手动对焦吗？如果是怎么办

提前致谢

Answer 1

有一种方法可以通过使用 Camera2Interop.Extender 访问低级 camera2 API 在 cameraX 中使用手动对焦.您应该像这样设置两个额外的选项来预览构建器:

void setFocusDistance(ExtendableBuilder<?> builder, float distance) {
    Camera2Interop.Extender extender = new Camera2Interop.Extender(builder);
    extender.setCaptureRequestOption(CaptureRequest.CONTROL_AF_MODE, CameraMetadata.CONTROL_AF_MODE_OFF);
    extender.setCaptureRequestOption(CaptureRequest.LENS_FOCUS_DISTANCE, distance);
}

并在构建您的 cameraX 预览请求时使用它:

float focusDistance = 0F; // example: infinite focus
Preview.Builder previewBuilder = new Preview.Builder();
setFocusDistance(previewBuilder, focusDistance);
preview = previewBuilder.build();
preview.setSurfaceProvider(viewFinder.getSurfaceProvider());

请注意，您还可以通过这种方式设置其他 camera2 CaptureRequest 选项。

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以下是查找 LENS_INFO_MINIMUM_FOCUS_DISTANCE(通常约为 10f 的值)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", "found it! " + discoveredMinFocusDistance);