If you have been playing around with your camera’s shutter speeds, you have probably figured out that there are hard maximum and minimum exposure times that your DSLR or mirrorless camera will allow you to select. At the top end, you have super-fast speeds like 1/8000s or even faster on some high-end cameras. Meanwhile, bottoming out usually happens at a timed exposure of 30 seconds, sometimes less than that.
Though you can’t shoot faster than the maximum speed your shutter is rated for, there is a way to shoot slower than the longest slow speed on your shutter speed dial. To do so, you need to make use of something called bulb exposures. But what is bulb mode, exactly? How does it work, and how can you use it for expressive results?
Today’s guide will be just about that! Without further ado, let’s get right into the topic of bulb exposures and their often overlooked utility in a variety of photographic contexts.
Bulb Mode in a Nutshell
Shooting in bulb mode allows you to keep your shutter open for very large amounts of time. That can be a few minutes, even hours, or days of exposure time!
This can be very useful when photographing the night sky, for instance, especially when trying to create star trails.
Bulb mode can also be used effectively in many other contexts. In landscape photography and in architectural scenes, bulb mode is essential when photographing stationary objects and natural features in poorly-lit conditions.
Prerequisites for Working in Bulb Mode
Not every camera allows you to use bulb mode. Because of the differences in controls and functionality of various camera models from different manufacturers, I recommend you study your camera’s user manual for precise information.
Even if your camera sports a bulb mode feature, not every bulb exposure is equal. For example, on some digital cameras, there may be a maximum bulb exposure time that your camera will not allow you to go past. That can be anywhere from a few minutes to an hour!
However, other cameras will give you complete freedom in programming ultra long exposures in bulb mode. In such cases, battery life may be the only real limit to how long you can keep your shutter open!
Also note that on the vast majority of cameras, bulb shooting is only available in manual mode. Make sure to set your mode dial to ‘M’ before enabling bulb exposures so you don’t accidentally waste any shots!
How to Enable Bulb Mode
How to access bulb mode once again differs depending on each individual camera model and brand. However, the vast majority of cameras use one of three layouts, so let’s address each of them below.
Method One: Engaging Bulb Mode via the Shutter Speed Dial
On some mirrorless cameras with full manual dials for your shutter speed setting, you may be able to simply switch over to Bulb mode on the fly.
Try rotating the shutter speed dial all the way past the longest setting until you reach the marking ‘B’. If you’re lucky enough to have a camera with such a simple layout, that’s all you need to do to enable bulb mode!
Method Two: Using Bulb Mode With the Command Dial
On most DSLRs that do not have traditionally marked dials, you may reach Bulb mode by using the command dial to cycle through shutter settings. Depending on the camera model and your personal setup, the correct dial will be either on the back of the camera by your right thumb or on the front by your right index finger.
Rotate the command dial far enough, and you’ll see a ‘B’ icon on your top LCD screen in place of the usual shutter speed numbers. Voilà, you have enabled Bulb mode!
Method Three: Bulb Mode Via the Camera Mode Dial or in Menu Options
Finally, some cameras may require you to use the camera modes dial and menu inputs on your camera’s LCD to configure bulb exposures. This can be a bit more complicated than the other two methods above. It requires you to go through a lengthier process to switch between regular, timed exposures mode and Bulb mode.
However, in the end, the result is obviously the same. Study the easiest methodology for your camera model according to the user’s manual, and you should be able to figure out the steps in no time!
Basic Bulb Mode Techniques to Know
Now that you understand how to enable Bulb mode, let’s see how to work with this exposure mode and take some exciting, beautiful photography!
Keeping Your Camera Stable in Bulb Exposure Photography
Bulb mode is strictly suitable for very long exposures, way beyond the usual limitations of your camera’s default shutter speeds. That means that stabilization is basically a must. Any small vibrations and even minor camera shake will show up on your final image.
It goes without saying that this makes a sturdy tripod an essential investment if you plan on getting anywhere near serious about bulb mode photography.
Of course, a tripod is not your one and only option. Some of you crafty landscape photography enthusiasts may find that a solid rock or a tree trunk can easily serve as a substitute, for example. Using your environment to stabilize your camera has the added benefit of reducing the need for hauling around heavy gear. It can also turn finding your composition into an even more fun process than usual.
On the other hand, it does allow you far less freedom in how you position yourself relative to your subject. In other words, you need to get lucky to find a suitable spot!
Using Bulb Mode With a Remote Shutter Release
There’s another important ergonomic consideration to make when shooting in Bulb mode.
Unlike shorter exposures, you need to time your bulb exposures by maintaining pressure on the shutter release button for as long as your exposure time is supposed to last. A one-second press and hold results in a one-second exposure, and so on and so forth.
Doing so by hand can not just become tiring. It can introduce a lot of unwanted camera shake and movement to your final image. That’s why almost all Bulb mode users tend to actuate the shutter release remotely.
Cable Releases for Long Exposure Photography
The most common kind of remote shutter release is also the most old-fashioned, by cable. A cable release is very simple, affordable, and easy to use. Just screw the cable into the appropriate socket on your camera and squeeze the trigger to open the shutter. Release to close.
Some release cables may feature a locking collar that you can twist to keep the shutter open without having to keep pressing down.
The Modern Alternative: Using a Wireless Remote Shutter Release
A more refined way of firing the shutter without accidentally disturbing your camera is by using a wireless remote shutter release button. These are usually powered by infrared receivers and are really easy to use, too. Just hold the receiver in your hand while maintaining a safe distance between yourself and the camera.
Press the shutter button on the receiver just like you would the one on your actual camera body. The remote shutter release should sync with your camera’s shutter instantly. Release the button to close the shutter.
Note that remote shutter releases are mostly not universally interchangeable. Do look up what’s compatible with your specific make and model of digital camera to find out what options you have!
Filters for Daytime Photography
Because Bulb mode will keep your shutter open for an exceptionally long amount of time, overexposure is a serious risk. Dialing down your ISO settings is a must, of course. But sometimes, even that may not be enough!
In cases where you’re not shooting in darkness outdoors and wish to maintain an even exposure, filters are your best friend. The most essential of them all is the neutral density filter, also called an ND filter for short.
This filter uniformly reduces the exposure level of your whole scene. In simpler terms, it absorbs a ton of light, making for a dark frame, so you can have much longer shutter speeds than otherwise possible. ND filters come in many grades or strengths, allowing you to pick the degree of exposure reduction that you need for every circumstance.
Besides the plain neutral density filter, there also exists a graduated version. Graduated ND filters are clear at the top and dark at the bottom, with a smooth gradient in between. This makes them really useful when shooting long exposures of sunrises or sunsets, for example.
You can position the dark hemisphere of the filter to cover the brightly-lit sky. This way, you can manage the stark contrast between foreground and background a bit more easily, allowing you to shoot in such tricky light conditions without getting overblown, white-out skies.
Bulb vs. Time Exposure Mode – What’s the Difference?
On some cameras, your shutter speed dial might offer one additional setting beyond bulb mode. ‘T’ for Time exposure mode operates similarly to Bulb mode.
It, too, allows you to create stunning long exposures by keeping the shutter open for a self-defined amount of time.
However, Time mode comes with a crucial difference. Instead of literally holding the shutter open by maintaining pressure on the shutter button, Time mode requires two quick taps of the shutter release button. The first tap begins the exposure, and the second closes the shutter, ending it. In between, no contact with the camera is necessary.
This crucial difference between Bulb mode and time exposure guarantees far lower chances of camera shake no matter what kind of shutter release you use. That’s why, when shooting extra long exposures, most photographers prefer to work with ‘T’ mode.
Unfortunately, not every digital camera shutter supports time exposures. Hence, do look up the technical specs of your model to figure out whether and how you can activate time mode yourself!
Handling Image Noise in Long Exposure Photography
If there is one perennial issue that plagues almost all digital long exposure photography, it’s image noise. As your shutter speed setting goes lower and lower, power consumption isn’t the only thing that increases proportionally.
Your camera, specifically the sensor, will continuously heat up while using bulb mode. Because most modern cameras are hardly designed with ultra long exposures in mind, they’re unlikely to feature the kinds of heavy-duty cooling systems that could prevent this fact from becoming an issue.
So, what can you expect when using Bulb mode for very long exposures in excess of a few minutes? In a word: noise, and lots of it. So-called thermal noise is different from high-ISO noise and often looks messier, too. Think of hot pixels, white specks all over your frame, and other kinds of artifacts.
One solution that helps prevent this kind of thermal noise from cropping up is to only use Bulb mode for extremely long exposures in very cold environments with lots of ventilation. Of course, that’s not always going to be an option though.
If you really want to master the art of sharp bulb images free of noise, make sure to consult the quick checklist below.
Your Checklist for Getting the Best Results Out of the Bulb Setting
The following is my top recommendation for how you should approach bulb mode exposures as a beginner. Make sure to internalize each of these steps and understand their significance the next time you head out to practice shooting!
- First, gather your gear. As before, I highly recommend a sturdy tripod, a remote release of some sort, plenty of reserve batteries, and filters if you’re going to be shooting in anything but very dark conditions.
- Set up your camera and figure out your composition. This is by far the most subjective and individual step on this list.
- If your exposure time is less than 8-10 minutes, then you can now set up either B or T mode and proceed to take the picture!
- If you’re going for an extra long exposure (for example, to capture expressive star trails), you have two options. Either you take the risk and make sure to remove any noise and artifacts in post processing, or you use so-called image stacking.
- Image stacking is a technique where you shoot at a slightly higher-than-minimum ISO and take a few shorter bulb exposures in a row. Later, you can create a composite of these images in post-processing which will look like one super-long exposure photograph.
- Another method involves long exposure noise reduction, which is a feature on many digital cameras. Select it using your camera’s built-in exposure menus, and use bulb mode as normal. You will notice that your shutter will actually stay open for twice as long as programmed. First, your camera captures your image, and then it superimposes a second frame that is completely blank, taken with the shutter blades closed. This is a time-consuming but efficient way to take noise-free long exposure photography.
Not so complicated, is it now? I hope you now have an idea of how bulb mode can not just be extremely useful but also fun and expressive! Make sure to apply these basic pointers to your next session, and I am certain you will be pleased with the results. Until next time!