The cable release has two positions – Normal mode and the Bulb mode.
This mode is the standard mode you will use to just trigger your camera at any situation. You will know that it is on Normal mode if the wheel of the cable release is twisted to the bottom:
This mode will come in handy for long time exposures wherein you won’t have to press the shutter for a long time. The cable release is in Bulb mode if the wheel of the cable release is twisted with a gap in between the wheel and the bottom:
To engage the cable release in Normal mode when it is in bulb,
Push down the wheel to release the cable release.
When using the cable release in Normal mode, push the release down. This will allow the pin to push the camera’s release.
To engage the cable release in Bulb mode,
When using the cable release in Bulb mode, turn the wheel counter-clockwise to engage it in Bulb mode. Twist it and the wheel will pop up a little.
Push the release down and it will lock. This will allow the pin to push the camera’s release and to leave the shutter open at your desired time. Please screw the shutter release into the camera before you push the cable release down.
When you have fulfilled your desired time, release the shutter by pushing down the disc – just as you would do to engage the normal mode. The cable release will snap back to its basic position.