you may start motion in setup mode using command: motion -s
and it will print quite a lot of messages to the screen:
$ motion -s
[0] Processing thread 0 - config file /etc/motion/motion.conf
[0] Motion 3.2.11 Started
[0] ffmpeg LIBAVCODEC_BUILD 3412993 LIBAVFORMAT_BUILD 3415808
[0] Motion running in setup mode.
[0] Thread 1 is from /etc/motion/motion.conf
[0] Thread 1 is device: /dev/video0 input 8
[0] Webcam port 0
[0] Waiting for threads to finish, pid: 11465
[1] Thread 1 started
[0] motion-httpd/3.2.11 running, accepting connections
[0] motion-httpd: waiting for data on port TCP 8080
[1] cap.driver: "uvcvideo"
[1] cap.card: "BUFFALO BSW20K05H Webcam"
[1] cap.bus_info: "usb-0000:00:1d.7-1"
[1] cap.capabilities=0x04000001
[1] - VIDEO_CAPTURE
[1] - STREAMING
[1] Supported palettes:
[1] 0: YUYV (YUV 4:2:2 (YUYV))
[1] index_format 6 Test palette YUYV (320x240)
[1] Using palette YUYV (320x240) bytesperlines 640 sizeimage 153600 colorspace 00000008
[1] found control 0x00980900, "Brightness", range -64,64
[1] "Brightness", default 0, current 0
[1] found control 0x00980901, "Contrast", range 0,64
[1] "Contrast", default 32, current 32
[1] found control 0x00980902, "Saturation", range 0,128
[1] "Saturation", default 64, current 64
[1] found control 0x00980903, "Hue", range -40,40
[1] "Hue", default 0, current 0
[1] found control 0x00980910, "Gamma", range 72,500
[1] "Gamma", default 100, current 100
[1] found control 0x00980913, "Gain", range 0,100
[1] "Gain", default 0, current 0