What Is Bulb Mode in Photography?

Photographers often feel frustrated by the 30-second shutter speed limit on many cameras. What they may not realize is that there is an easy way around this limitation – if you know how to use it. The solution is known as bulb mode.

What Is Bulb Mode on Your Camera?

Bulb mode is simply a shutter speed option that you can select in Manual mode on your camera. It allows your shutter speed to be any length you choose: one second, one minute, 17 minutes, or anything else.

The key with bulb mode is that your camera’s shutter stays open for as long as you hold down the shutter release button. The limit on your Bulb exposure depends on the camera – sometimes 30 minutes, sometimes as long as you like (or until your battery dies).

Accessing Bulb Mode

Not all cameras have bulb mode today, but most DSLRs and mirrorless cameras do. This includes nearly every Nikon, Canon, Sony, Fuji, Olympus, and Pentax DSLR or mirrorless camera on the market.

It is easy to check if your camera has a bulb mode. Turn your camera to Manual, and shift your shutter speed as long as it can go. Usually, after the 30 second mark, your camera will show the letter “B” as your shutter speed. This is your bulb mode!

How to Use Bulb Shutter Speeds

If you’ve never used bulb mode before, you may be confused why the “B” option appears to take very short exposures. For example, say that you have bulb mode enabled and you simply press the shutter release like normal. In that case, you will only capture an exposure of a fraction of a second.

This is because bulb mode requires that you hold down the camera’s shutter release button during the entire exposure. If you hold down the shutter button for 45 seconds, that will be your exposure. But if you simply press and release the shutter button like normal, you may get a 1/2 second exposure or even less.

Generally, there is no reason to use bulb mode if you are under 30 seconds (or whatever your camera’s longest native shutter speed may be). The main exception is if you are photographing stars at night, and you want to be very precise about your shutter speed in order to avoid star trails. But even this is usually overkill.

One big problem remains: Pressing down on the camera’s shutter button in bulb mode almost always shakes the camera and introduces blur. That is simply because your hands themselves inevitably shake; even with the steadiest tripod on the market, you’re likely to get blurry photos if you use bulb mode like this.

So, what can you do about it? The next section covers the easiest solution.

How to Capture Tack-Sharp Long Exposures

Often, the best solution to avoid blurry exposures in Bulb is not to touch your camera at all while it’s taking a picture. Instead, trigger your camera to take a photo using a remote shutter release!

Every popular camera on the market today has a compatible remote shutter release. Here’s the simplest one for Nikon D3000, D5000, and D7000 series cameras (excluding the D3500, which doesn’t have an IR sensor and is controlled via your smartphone instead). Here’s the comparable option for most Canon DSLRs, including the Rebel lineup.

If you have a different camera, it is trivial to search for your desired remote shutter release here. Just type your camera name followed by “remote release.”

Some of these remotes are wireless (infrared) while others are wired cables. You can also buy certain remotes with additional options for time lapses and other specialty photography. If bulb photography is your only goal, however, it does not matter; any cable release on the market will let you use bulb mode the proper way – without touching the camera.

Note that some remote releases have a locking mechanism to hold down the external shutter button automatically as long as you like. Others allow one press to start the exposure and a second press to end it. A few cameras even have a bulb mode that you can trigger from your phone, if you so desire.

Regardless – by using bulb mode with an external remote, you are no longer touching your camera during the exposure. That way, you can capture extremely sharp ultra-long exposure photos with ease.

Bulb vs Time Exposure Mode

A few cameras today have something even better than bulb mode, called time mode. In this case, you don’t need to hold down the shutter release button at all. You simply need to press the shutter button once to start the exposure, and again to end it.

I don’t know why every camera on the market does not have this extremely useful feature, but that’s the way things are. Luckily, many new cameras today have this option, even some less expensive cameras like the Nikon D5600. If your camera has a time exposure mode, there are few reasons to use the standard Bulb option any longer. Time Mode has all the same benefits without the drawback of using a remote shutter release.

Time Mode is accessed exactly the same as bulb mode – by going beyond a 30 second shutter speed in manual mode. Cameras with a time exposure option generally label it as “T.”

Image Noise with Long Exposure Photography

I love using bulb mode and time mode in dark conditions. The results you’ll get beyond the ordinary 30 second limit are often incredible. But you do need to watch out when your shutter speeds are too long, especially several minutes or more. If you’re not careful, your image quality can suffer.

Specifically, camera sensors heat up quite a bit if your exposure is long enough – the very reason to use Bulb exposures in the first place. This heat translates to image noise. This “thermal noise” is less pronounced if you are shooting in cold conditions, but it still pops up eventually. On top of that, because your exposure is so long, any hot or stuck pixels on your camera sensor will appear exaggerated.

The easy solution is to avoid ultra-long exposures, especially longer than 8-10 minutes, but that’s not always feasible. If you really need extreme shutter speeds like this, you have a couple options.

First, you could enable something called Long Exposure Noise Reduction on your camera. That setting causes your camera to take a second exposure after your bulb mode shot – this time with the camera shutter closed, resulting in a dark frame. Your camera will then subtract the second frame from the first, decreasing some thermal noise and minimizing hot pixels.

But long exposure noise reduction means your camera spends twice as long taking each picture, since it literally captures two photos each time. That’s not ideal when you’re already shooting 10 minute exposures or more.

Instead, some photographers will take a series of shorter exposures – still using Bulb or Time exposure modes – in combination with a slightly higher ISO. They’ll wait a moment from shot to shot so the camera can cool down. With this technique, you can average out the image noise in software like Adobe Photoshop. It is a way to “simulate” extra long exposures without actually taking them. However, it’s also a bit of an advanced technique. You may be better off sticking with single-image Bulb photos until you’ve practiced it a bit.

Conclusion

Hopefully you found this article on bulb mode to be useful, especially if you are just starting out in long exposure photography. The world looks completely different with multi-minute exposures. It’s something I think everyone should try at some point – regardless of your genre of photography.

That said, you need to do it right. It’s easy to get blurry photos in bulb mode if you don’t use a remote shutter release. And, if your shutter speed gets especially long, you’ll need to keep an eye out for image noise and minimize it if possible (potentially with long exposure noise reduction or image stacking).

At the end of the day, bulb and time modes are great tools in a photographer’s kit. If you have any questions or recommendations on how to use them effectively, please let me know below!