Android Camera2 API How to get initial focus point distance with inbuilt AUTOFOCUS routine of camera?

Question

So basically I want to get the focus distance of lens when the focus mode is AUTO.

Currently I am working like this:

• Assuming CONTROL_AF_MODE is set to CONTROL_AF_MODE_AUTO by default.

• Trying to get CaptureRequest.LENS_FOCUS_DISTANCE which returns 0.0 on NEXUS 5 virtual device and null on Redmi Note 3.

Is it the correct logic?

Answer 1

Generally the logic is correct. Just check a few details:

1. Make sure your device and specific camera support auto focus by checking LENS_INFO_MINIMUM_FOCUS_DISTANCE.
2. Make sure CONTROL_AF_STATE is at least not CONTROL_AF_STATE_INACTIVE. Most likely you need to wait until it's actually focused.

Also note the type of this value is different on different devices. Check LENS_INFO_FOCUS_DISTANCE_CALIBRATION to find out if it's a real distance or just some synthetic value.