ShutterBug simply does one thing. It takes repeated images from your video source and places them in a file in JPEG format, ready to be downloaded over the web. It has many nice features...
• Automatic Exposure -- no more fiddling with that exposure control when the lighting changes
• Spot Metering -- you place a rectangle over the object of interest and the exposure is optimised within this region.
• Works in the background - you can use your mac for other things !
• Time Stamping -- sounds useful anyway.
• JPEG comments -- Add a caption to your image.
• Auto Start Option -- can be started up automatically.
IF YOU DECIDE TO USE SHUTTERBUG ON THE WEB THEN YOU MUST PAY YOUR SHAREWARE FEE (see acompanying files for more information on how to do this).
There are two settings dialogs which affect the main operation of ShutterBug. These are described in turn below
Automatic Exposure
Automatic Exposure is calculated by averaging the pixel values inside the Spot Meter rectangle (the black rectangle which appears superimposed on the Viewfinder). This rectangle can be set by choosing the Spot-meter command (from the Photo Menu) and clicking the mouse in the top left of the desired rectangle and dragging to the bottom right. Usually you want this rectangle to enclose the point of interest in the scene as the automatic exposure algorithm will look at this region only. You can also set the spot meter without using the menu command, by clicking and dragging in the viewfinder window when the cursor is a crosshair '+'.
The other parameters of the Automatic Exposure system are the spot meter grid, desired brightness and the exposure damping. These can be alered from the viewfinder preferences dialog. The desired brightness is a number between 0 and 100 which determines the average brightness of the pixels in the Spot-meter Rectange. I recommend the default value of 50. The exposure damping determines how quickly the exposure is adjusted to compensate for changes in the outside brightness. If this is a small value (like 50 or so) then the exposure will change relatively slowly. I recommend smaller values if you have a long time (like 1 minute) between photos, because the camera has plenty of time to settle to the optimum exposure situation. If the light level is changing very rapidly (in a place where a door is being opened at regular intervals increasing the brightness suddenly) then a higher value of the damping is indicated. Higher values may have the unwelcome side effect of making the damping oscillate around its euilibrium value.
Finally the spot-mater grid is simply the number of samples on one side of the spot meter grid. The default value of ten can be increased if you would like better brightness measurement, but you should not increase it above 30 or you will get significant slowdowns and no noticable improvement in brightness.
JPEG quality
The JPEG quality setting determines the quality of the compressed picture and represents a tradeoff. On one hand a low quality setting will drastically reduce the picture size (5% gives sizes of a few kilobytes). On the other hand low quality settings will reduce the resulotion of fine detail. I recommend 5-10 % for web sites.
Auto Start
To configure ShuterBug in the autostart mode you will have to register (and pay your shareware fee). Once you have registered then follow these simple instructions. 1) Set Up The Automatic exposure. 2) Choose the Auto Start from the photo menu. Choose Begin Photo Session from the photo menu. 3) After you have been prompted for the filename, ShutterBug will save the first photo and store the file information in the preferences. You can now quit and from now on if ShutterBug is restarted it will go automatically into a photo session.
This all means that you can put an alias of ShutterBug into your Startup Items folder (inside your system folder) and then your web page will be up and running automatically.
Hints...
Use a really low JPEG quality setting. This will save your web server from sending large files and on the low resolution of a QuickCam this does not seem to make much difference to the final image. Experiment and see what you find to be best, but the reduction in file size is well worth the slight reduction in quality in most circumstances.
