android.hardware.camera预览：如何手动设置曝光时间，快门速度，光圈和ISO

Question

I am working on an app where I have a camera preview and I take pictures in dark settings. Therefore, I need a way to manually control the exposure time of the camera and the settings of shutter speed, aperture, and iso.

I know it must be possible because the application Long Exposure Camera 2 (by AAASDream) has a way to manually change the exposure time and it works perfectly. I am not referring to the exposurecompensation which I already tried but was not sufficient enough.

Based off of this post , I tried setting

Camera.Parameters params = camera1.getParameters();
params.set("mode", "m");
params.set("aperture", 80);
params.set("shutter-speed", 9);
params.set("iso", 1600);

But this did not work at all.

Is there any hidden API or setting that I can use or any third party library I can use to accomplish this.

All help is appreciated, thanks.

Answer 1

I think there is no way to manually set the above mentioned values in android.hardware.camera. But it looks like the new version android.hardware.camera2 supports those functionalities.

Answer 2

Yes, it isn't possible to manually set one of the two mentioned parameters directly via the Camera 1 API. Neither the characteristics can be queried via a standardized method, because it isn't supported.

Of course there is a way around, to query or to set such properties via special methods, as relime9 currently mentioned:

// query all the settings you camera support (API 1)
mCamera.getParameters().flatten();
// set parameters - e.g. aperture
mCamera.getParameters().set("aperture", "80");

Additionally the specific device must support such a setting, which vary from device to device. On some devices there can be set certain values and with other you can't and can only use the ''auto'' mode.

For this reason they developed the Camera 2 API, which is more standardized and supports such functionalities.