Glossary
Bulb mode
Also called: B mode, bulb
A shutter mode that keeps the shutter open for as long as you hold the release.
Bulb mode is how you take exposures longer than the camera's slowest shutter speed, typically a few seconds to many minutes. It is named after the old rubber bulb that fired pneumatic shutter releases. Long bulb exposures need a tripod and a timer; Zone Light Meter has a built-in bulb timer that haptics or speaks the count for hands-free use.
Where this shows up in the app
Bulb mode integration
Bulb is a first-class shutter setting across the metering pipeline.
Equipment tab > Cameras / Lenses (hasBulb checkbox), surfaces in Viewfinder shutter recommendations
How the Bulb Timer works
Stopwatch for long exposures with optional haptic and voice cues.
Tools tab > Bulb Timer
Bulb auto-lock via gyro when steady
Timer waits for the phone to stop wobbling before it starts the count.
Tools tab > Bulb Timer > Gyro auto-start toggle