What you'll learn

1. How to use bulb on your camera

2. Why bulb is really useful

3. How to avoid camera shake

Most cameras have a maximum shutter speed of around 30 seconds, but you can easily get around this by using bulb mode.

What you'll need

  • Camera with a Manual or Bulb Mode
  • Tripod
  • Cable Release (e.g. Triggertrap Mobile)


The name “bulb”, often abbreviated to “B” on your camera, originates from an old form of cable release that required you to squeeze an air bulb in order to open the shutter of the camera. The shutter would then close when the bulb was released.

When you set the shutter speed to bulb on a DSLR camera, it enables you to press and hold the shutter button down in order to open the shutter, and release it to close the shutter, allowing you to freely select your shutter speed to be as long or as short as desired.

Sometimes bulb is available as a mode on your camera, usually marked by a B on the mode dial. With other cameras, you will need to start by setting the camera to manual (or “M”), and then winding the shutter speed all the way down. One setting beyond than the longest exposure should be “B” for Bulb. If you are unsure how to set your shutter speed, see our manual exposure tutorial.

Bulb also allows you to control your shutter from a cable release, sometimes known as a shutter remote control. A cable release is a really useful accessory for any photographer. It simply moves the shutter release button away from the camera, allowing you to trigger the camera without touching it.

Using a cable release is perfect for long exposure photography where even the slightest shake could ruin your exposure. For example, you might want to take a three minute exposure in order to try light painting. You will need to set your shutter to bulb so that you can keep the shutter open for the full three minutes. You can set your shutter to bulb and then insert your cable release to the cable release port on your DSLR. You can now use your cable release to lock open your shutter without disturbing your camera, create your light painting, and then close the shutter without disturbing your camera set up!

Setting up

The finished setup

At this point, you should have your camera on a tripod, set to bulb and, if you’re using one, your cable release should be plugged in.

Capturing the photos