hi @kll,
pity of Gohai, but hopeful you and/or others can help 
as mentioned in my original post, I’m using a raspberry pi 3b+, with a new image of raspbian (September update) on it. I installed processing through the terminal (Download - Processing for Pi).
The camera is the raspberry pi camera V1.3 connected to the slot next to the HDMI port and works through terminal like mentioned before.
terminal responses:
Raspberry Pi 3 Model B Plus Rev 1.3
DEBIAN buster
Linux version 4.19.75-v7+
"raspistill" Camera App (commit )
Camera Name ov5647
Width 2592, Height 1944, filename (null)
Using camera 0, sensor mode 0
GPS output Disabled
Quality 85, Raw no
Thumbnail enabled Yes, width 64, height 48, quality 35
Time delay 5000, Timelapse 0
Link to latest frame enabled no
Full resolution preview No
Capture method : Single capture
Preview Yes, Full screen Yes
Preview window 0,0,1024,768
Opacity 255
Sharpness 0, Contrast 0, Brightness 50
Saturation 0, ISO 0, Video Stabilisation No, Exposure compensation 0
Exposure Mode 'auto', AWB Mode 'auto', Image Effect 'none'
Flicker Avoid Mode 'off'
Metering Mode 'average', Colour Effect Enabled No with U = 128, V = 128
Rotation 0, hflip No, vflip No
ROI x 0.000000, y 0.000000, w 1.000000 h 1.000000
Camera component done
Encoder component done
Starting component connection stage
Connecting camera preview port to video render.
Connecting camera stills port to encoder input port
Closing down
Close down completed, all components disconnected, disabled and destroyed
(image of camera appears on display and takes a photo)
Driver Info:
Driver name : bm2835 mmal
Card type : mmal service 16.1
Bus info : platform:bcm2835-v4l2
Driver version : 4.19.75
Capabilities : 0x85200005
Video Capture
Video Overlay
Read/Write
Streaming
Extended Pix Format
Device Capabilities
Device Caps : 0x05200005
Video Capture
Video Overlay
Read/Write
Streaming
Extended Pix Format
Priority: 2
Video input : 0 (Camera 0: ok)
Format Video Capture:
Width/Height : 1024/768
Pixel Format : 'JPEG' (JFIF JPEG)
Field : None
Bytes per Line : 0
Size Image : 786432
Colorspace : JPEG
Transfer Function : Default (maps to sRGB)
YCbCr/HSV Encoding: Default (maps to ITU-R 601)
Quantization : Default (maps to Full Range)
Flags :
Format Video Overlay:
Left/Top : 150/50
Width/Height: 1024/768
Field : None
Chroma Key : 0x00000000
Global Alpha: 0xff
Clip Count : 0
Clip Bitmap : No
Framebuffer Format:
Capability : Extern Overlay
Global Alpha
Flags : Overlay Matches Capture/Output Size
Width : 1024
Height : 768
Pixel Format : 'YU12'
Streaming Parameters Video Capture:
Capabilities : timeperframe
Frames per second: 30.000 (30000/1000)
Read buffers : 1
User Controls
brightness 0x00980900 (int) : min=0 max=100 step=1 default=50 value=50 flags=slider
contrast 0x00980901 (int) : min=-100 max=100 step=1 default=0 value=0 flags=slider
saturation 0x00980902 (int) : min=-100 max=100 step=1 default=0 value=0 flags=slider
red_balance 0x0098090e (int) : min=1 max=7999 step=1 default=1000 value=1000 flags=slider
blue_balance 0x0098090f (int) : min=1 max=7999 step=1 default=1000 value=1000 flags=slider
horizontal_flip 0x00980914 (bool) : default=0 value=0
vertical_flip 0x00980915 (bool) : default=0 value=0
power_line_frequency 0x00980918 (menu) : min=0 max=3 default=1 value=1
sharpness 0x0098091b (int) : min=-100 max=100 step=1 default=0 value=0 flags=slider
color_effects 0x0098091f (menu) : min=0 max=15 default=0 value=0
rotate 0x00980922 (int) : min=0 max=360 step=90 default=0 value=0 flags=modify-layout
color_effects_cbcr 0x0098092a (int) : min=0 max=65535 step=1 default=32896 value=32896
Codec Controls
video_bitrate_mode 0x009909ce (menu) : min=0 max=1 default=0 value=0 flags=update
video_bitrate 0x009909cf (int) : min=25000 max=25000000 step=25000 default=10000000 value=10000000
repeat_sequence_header 0x009909e2 (bool) : default=0 value=0
h264_i_frame_period 0x00990a66 (int) : min=0 max=2147483647 step=1 default=60 value=60
h264_level 0x00990a67 (menu) : min=0 max=11 default=11 value=11
h264_profile 0x00990a6b (menu) : min=0 max=4 default=4 value=4
Camera Controls
auto_exposure 0x009a0901 (menu) : min=0 max=3 default=0 value=0
exposure_time_absolute 0x009a0902 (int) : min=1 max=10000 step=1 default=1000 value=1000
exposure_dynamic_framerate 0x009a0903 (bool) : default=0 value=0
auto_exposure_bias 0x009a0913 (intmenu): min=0 max=24 default=12 value=12
white_balance_auto_preset 0x009a0914 (menu) : min=0 max=10 default=1 value=1
image_stabilization 0x009a0916 (bool) : default=0 value=0
iso_sensitivity 0x009a0917 (intmenu): min=0 max=4 default=0 value=0
iso_sensitivity_auto 0x009a0918 (menu) : min=0 max=1 default=1 value=1
exposure_metering_mode 0x009a0919 (menu) : min=0 max=2 default=0 value=0
scene_mode 0x009a091a (menu) : min=0 max=13 default=0 value=0
JPEG Compression Controls
compression_quality 0x009d0903 (int) : min=1 max=100 step=1 default=30 value=30
just checked raspi-config for the kms settings and I hadn’t changed it before, so I assume it was correct? (just selected the legacy just in case).
processing is version 3.5.3 and I installed all libraries through the built-in library manager.
I honestly don’t know what it could be…
