Daytime images overexposed on bullseye

[varunreddyputta]

Hi,

I have a RpiHQ with arducam 180 M12 fisheye lens.
I have been to trying various daytime settings but my image is overexposed even with 1us, 1 gain and -100 brightness (I am on bullseye). I have removed the IR filter and hence set manual WB with 1.2 and 2 for blue and red.

I am trying to figure if this is an issue with my settings or my dome. Has anyone faced this issue? Would appreciate anyone's help.

Here is a typical run

Capture command: libcamera-still --output '/home/pi/allsky/tmp/image-20221205135520.jpg' --timeout 1 --nopreview --width 4056 --height 3040 --shutter 1 --gain 1 --exif IFD0.Artist=li_1_1 --awbgains 1.2,2 --saturation 1 --brightness -1 --quality 95 > /tmp/capture_RPiHQ_debug.txt 2>&1
Dec 5 13:55:23 allsky allsky.sh[31447]: > exposure: 0.000 sec, mean: 0.955, mean_value: 0.100, diff: -0.855
Dec 5 13:55:23 allsky allsky.sh[31447]: > MeanCnt: 37, historySize: 3
Dec 5 13:55:23 allsky allsky.sh[31447]: > i=1: mean_history[2]=0.955 exp_history[2]=-706
Dec 5 13:55:23 allsky allsky.sh[31447]: > i=2: mean_history[0]=0.955 exp_history[0]=-706
Dec 5 13:55:23 allsky allsky.sh[31447]: > i=3: mean_history[1]=0.955 exp_history[1]=-706
Dec 5 13:55:23 allsky allsky.sh[31447]: > mean_forecast: 0.954, values: 9, mean_diff: 0.855
Dec 5 13:55:23 allsky allsky.sh[31447]: > ExposureChange: 50 (0)
Dec 5 13:55:23 allsky allsky.sh[31447]: > ExposureTime_s <= 1 microsecond can't go any lower!
Dec 5 13:55:23 allsky allsky.sh[31447]: > Mean: 0.955, diff: 0.855, Exposure level:-706 (0), Exposure time:1 us, analoggain:1.00
Dec 5 13:55:23 allsky allsky.sh[31447]: > Got exposure: 50.00 ms, shutter: 1 us, quickstart: 0, mean=0.955
Dec 5 13:55:23 allsky allsky.sh[31447]: > Saving DAY image 'image-20221205135520.jpg'

[EricClaeys]

@varunreddyputta What's the F-stop of your lens? If it's fast I can see this happening. I'm pretty sure I've had situations where it was hitting the 1 microsecond minimum.
It's also possible removing the IR filter made the sensor slightly more sensitive.
I suggest asking on the libcamera GitHub page to see if there's another setting to make the camera less sensitive, or if they have any other suggestions.

[varunreddyputta]

@EricClaeys Thank you. It's an F2 lens. I will check with libcamera Github.