[BUG] Setting manual focus does not always work.

Describe the bug Manual focus setter does not always work.

With the exact same code and settings, sometimes the focus is set to the desired value (130) and sometimes to 0. The behavior seems to change more frequently if I disconnect and reconnect the device, or if I set/unset the autofocus. The behavior also changes when I leave the device inactive for some minutes.

I managed to reproduce this behavior with two different devices, connected to two different computers. I also tried to change the USB port.

Sometimes I also notice an abrupt change in focal length during the acquisition of the first frames, even though the autofocus is disabled and the manual focus is set to 130. After this abrupt change, the focus sets either to 0 or to the desired value.

To Reproduce I am currently using the following pipeline. At the end of it I set the autofocus to OFF and manual focus to 130.

pipeline = dai.Pipeline()

# RGB (center) Camera
center_camera = pipeline.createColorCamera()
center_camera.setPreviewSize(1280, 800)
center_camera.setBoardSocket(dai.CameraBoardSocket.RGB)
center_camera.setResolution(dai.ColorCameraProperties.SensorResolution.THE_1080_P)
center_camera.setInterleaved(True)
center_camera.setColorOrder(dai.ColorCameraProperties.ColorOrder.RGB)

# left camera
left_camera = pipeline.createMonoCamera()
left_camera.setResolution(dai.MonoCameraProperties.SensorResolution.THE_800_P)
left_camera.setBoardSocket(dai.CameraBoardSocket.LEFT)

# right camera
right_camera = pipeline.createMonoCamera()
right_camera.setResolution(dai.MonoCameraProperties.SensorResolution.THE_800_P)
right_camera.setBoardSocket(dai.CameraBoardSocket.RIGHT)

# center stream
center_stream = pipeline.createXLinkOut()
center_stream.setStreamName("center")
center_camera.preview.link(center_stream.input)

# left stream
left_stream = pipeline.createXLinkOut()
left_stream.setStreamName("left")
left_camera.out.link(left_stream.input)

# right stream
right_stream = pipeline.createXLinkOut()
right_stream.setStreamName("right")
right_camera.out.link(right_stream.input)

# camera control
cam_control_in = pipeline.createXLinkIn()
cam_control_in.setStreamName("cam_control")
cam_control_in.out.link(center_camera.inputControl)

# device
device = dai.Device(pipeline, usb2Mode=False)
device.startPipeline()
device.setLogLevel(dai.LogLevel.DEBUG)

# set focus
q_control = device.getInputQueue(name="cam_control")
cam_control = dai.CameraControl()
cam_control.setManualFocus(130)
cam_control.setAutoFocusMode(dai.RawCameraControl.AutoFocusMode.OFF)
q_control.send(cam_control)

Expected behavior Camera focus should be set to the same length every time I run the script.

Screenshots Running the script - this time it set the focus to 130.

Running the exact same script again - this time the focus is wrong.

[alex-luxonis]

We have a work-in-progress branch with a workaround for this issue: https://github.com/luxonis/depthai-python/pull/336 https://github.com/luxonis/depthai-core/pull/191

[LucaBonfiglioli]

Yeah, we noticed that as well with autofocus initially enabled, sometimes it needs more than one set command to get to take effect. It’s some bug on the FW side.

For now, could you set manual focus initially at pipeline creation time, this should fix that behavior. Like:

center_camera.initialControl.setManualFocus(130)

# This may be redundant when setManualFocus is used
center_camera.initialControl.setAutoFocusMode(dai.RawCameraControl.AutoFocusMode.OFF) 

And if you want to set other types of controls at pipeline creation time, need to use the develop branch. We’ll probably make a release as well next week, to include it in main.

Using initialControl instead of “camControl” input queue seems to fix the issue. Thank you.