Some are Boojums--

It turns out that it's fairly easy to use a linux box to take pictures using my Nikon D50 and display the results to the screen:

$ gphoto2  --capture-image --interval 10 -F 2 --hook-script showpic.sh

The above takes two frames ten seconds apart (making a D50 into a very expensive webcam). Alternatively, I could use the following to use the camera normally but have the pictures show up on the computer screen:

$ gphoto2 --capture-tethered --hook-script showpic.sh

The "hook script" is what does the actual display after each shot:

$ cat showpic.sh
#! /bin/bash

self=`basename $0`

case "$ACTION" in
    init)
    echo "$self: INIT"
    # exit 1 # non-null exit to make gphoto2 call fail
    ;;
    start)
    echo "$self: START"
    ;;
    download)
    echo "$self: DOWNLOAD to $ARGUMENT"
    eog ${ARGUMENT} &
    ;;
    stop)
    echo "$self: STOP"
    ;;
    *)
    echo "$self: Unknown action: $ACTION"
    ;;
esac

exit 0

Pretty darn cool!