From: Northridge, CA USA
Registered: Jun 2003
posted December 05, 2007 12:19 PM
As I recall, when you use the cable release and put the camera in the "T" position, then when you press in on the cable release the shutter opens and when you release the cable the shutter closes and the film advances.
This is useful if you need to do a long exposure of a subject and would be used in a case where you set up an automatic system to take say one frame every 30 seconds and you needed a one second exposure because of light levels (say roots growing out of a planted seed). When projected at 24 fps per second, each second of screen time would be 12 minutes of actual clock time.
Also would be useful in stop motion or puppet photography where you need great dept of field and hence a very small f/stop and didn't want a lot of blazzing lights so you could do your version of a George Pal Short, etc.