Bulb mode | long exposures beyond the 30-second mark (2024)

Once you go slower than this, the display switches to showing seconds, followed by a double quote mark and then tenths of a second. For example, one third of a second is written as 0”3 and two-and-a-half seconds would be displayed as 2”5. This will continue down to thirty seconds (30”). The actual shutter speed sequence you see will depend on whether you choose to see shutter speed in half stop or one third stop intervals. Shown above are the viewfinder representations of the shutter speeds 1, 1.5, 2, 3, 4, 6, 8, 10, 15, 20 and 30 seconds.

Canon EOS 5D Mark IV, 180 seconds at f22. Photo by Oliver Plattner on Unsplash

Getting started with bulb mode

There are some simple rules to help you get started when shooting with bulb mode.

• Because you are operating your camera manually, it will not suggest an exposure. Initially, to help gauge the correct shutter speed, set your camera to shutter-priority (Tv) mode and test the exposure at the default maximum of 30 seconds, with the lowest available ISO settings. If the aperture values flashes when you half-press the shutter button, then there is too much light and your image will be overexposed. If this happens, you either need to return when there is less light or use a Neutral Density filter. If the aperture doesn’t flash, then 30 seconds is a good starting point.
• If the exposure is 30 seconds at f8, reducing the aperture to f22 will allow to shoot with an exposure time of 4 minutes (decreasing the aperture by one stop to f11 will give 1 minute, by two stops to f16 will give two minutes – the exposure doubles each time you reduce the aperture by one stop).
• Set the ISO as low as possible. For APS-C cameras this is ISO 100. For full frame cameras, you have the option to set ISO 50 via the expanded ISO settings.
• Set the narrowest aperture available – on some lenses this is f22, on others it’s f32.
• If your camera does not have a built-in timer or elapsed time function, use a stopwatch/timer on phone.
• Make an exposure, then view on the LCD screen. Modify the settings if necessary. Small changes will not be significant. Double or halve the exposure time and view the image again.

Canon EOS 5DS R, 270 seconds at f13. Photo by Ian Simmonds on Unsplash



Using a remote switch

With EOS cameras, long ‘bulb’ exposures are usually triggered using a simple electrical remote switch such as the Canon RS-80N3 or Canon RS-60E3. These devices have a shutter button that can be locked into position to keep the shutter open indefinitely. If you tried to trigger a bulb exposure using just the normal shutter button you would have to hold your finger on the button for the duration of the exposure, which is not very practical.

There’s also the Canon Timer Controller TC-80N3 which offers a programmable shutter release to time your long exposures.

As well as using bulb mode for smooth water effects and dreamy clouds, longer exposure times also lend themselves to astrophotography. Canon EOS 6D, 39 seconds. Kayvan Mazhar via Unsplash



Using the Bulb timer feature

Some of the more advanced camera models introduced since 2014 feature an option called ‘Bulb timer’. This setting, found in the red Shoot menu, can only be accessed once the camera is set to the bulb (B) mode.

When in bulb mode, naviagte to the Bulb timer, then press SET. Select ‘Enable’ to turn the timer on, then press the INFO button to set up the length of the exposure in hours, minutes and seconds.

Once set up, fire the camera to start the bulb timer, then the camera will close the shutter automatically at the end of the programmed time period.

ND filters

If there’s simply too much ambient light to achieve a sufficiently slow shutter speed, then there’s one accessory that can help you. Neutral density filters, which are available both as screw-on circular filters and square drop-in filters (for use with a suitable holder), reduce the amount of light entering your lens so that you can shoot with extended shutter speeds, even in daylight.

ND filters can compromise autofocus performance. With some of the less dense filters – ND2 to ND8 (which cut out from one stop to three stops of light) – you should still be able to focus as normal. With darker filters, you may need to focus on your subject before fitting the filter to your lens.

You can also use Live View with an ND filter. Canon’s Dual Pixel CMOS sensor-based focusing system nowadays is rated to a far lower EV rating than the standard focusing in DSLRs, often able to see in light levels two or three stops below what was previously possible.

An extended exposure can even give water a misty appearance. When shooting in daylight, an ND filter is essential to achieve long shutter speeds. Canon EOS 5D Mark II, 148 seconds at f16. © Billy Stock.

SUMMARY

Bulb mode definitely isn’t an every day setting. You need just the right amount of light, or at least the ability to control it via means of a Neutral Density filter. However, when used creatively with the right subject it can produce stunning images. Seascapes, light and star trails, plus astrophotography all make for ideal subjects for your bulb exposures. Just be sure to shoot on a tripod and avoid touching the camera during the exposure as any movement will result in blur.

If you’re struggling to get your settings right, try the step-by-step process above in Tv mode, before switching to Manual mode. This way you’ll be able to tell whether or not the effect you’re after is achievable in the current conditions and light levels.