An introduction to long exposure photography
Long exposure photography (or long shutter speed photography) is a photographic technique where the camera's shutter remains open for a long period of time, allowing more light to reach the camera sensor.
There is no strict definition as to what constitutes a long exposure (as opposed to a 'normal' exposure) but I generally think that it is any shutter speed which can blur motion (so anything longer than around 1/3 of a second up to minutes!). This blur is either caused by motion in the scene, or motion of the camera.
A long shutter speed creates an effect in the photo where moving elements in the scene (like water, clouds, or lights) appear blurred or stretched, whilst stationary objects in the scene remain sharp and in focus.
The technique is often used to capture motion in a creative way, by either blurring the motion of moving elements in the scene (water, clouds, stars) or by intentionally blurring stationary objects in the scene by intentionally moving the camera while the shutter is open (the ICM technique).
Long exposures always require a tripod to keep the camera steady during the extended exposure time, preventing camera shake and ensuring sharpness in the static parts of the image. The only exception to this is for ICM, where the blurring effect in the image is caused by intentionally moving the camera.
1. Common uses & subjects
There are a wide range of potential creative applications for long exposure photography, including:
Light Trails
Car lights: Capturing the motion of vehicle lights on roads at night creates streaks of light, highlighting the flow of traffic. See this blog on light trails.
Star trails: By keeping the shutter open for several minutes or hours, you are able to capture the Earth's rotation, resulting in beautiful star trails across the sky.
Water
Flowing rivers or waterfalls: Long exposure creates a smooth, misty effect on moving water, giving it a dreamlike quality.
The sea: Similar to rivers and waterfalls, long exposures of the sea can create a tranquil, fog-like appearance, smoothing out the waves.
Cloud movement
Capturing the slow movement of clouds, especially during windy conditions, can add motion and drama to landscape images, showing the clouds streaking across the sky.
Astrophotography
Milky Way: A long exposure (but not too long!) captures the Milky Way without creating star trails, highlighting the detailed structure of the galaxy.
Meteor showers: Long exposures capture meteors streaking through the sky, creating dazzling night sky images.
Low Light & Night Photography
Cityscapes: Long exposure helps illuminate dark scenes, capturing fine details in urban environments at night, such as street lights, building lights, and the movement of people or vehicles.
Fireworks: Extended shutter times capture the full explosion and trailing effects of fireworks.
Intentional Camera Movement (ICM)
Creative blur effects: By deliberately moving the camera during a long exposure, can create abstract and painterly images, especially with colorful subjects. See this blog on ICM.
Light Painting
Drawing with light: By moving a light source (like a torch or LED), you can "paint" designs or shapes into a scene, captured as streaks or patterns of light in the image.
Motion Blur
Human or animal movement: Long exposure can capture the motion of people walking, running, or moving through a scene, creating ghostly or blurred figures.
Fair ground rides: Moving rides, such as Ferris wheels, are often photographed using long exposure to show their circular motion.
Fire and Sparks
Steel wool spinning: By spinning burning steel wool, you can capture the movement of the sparks, creating circular, dynamic patterns of light in a long exposure shot.
2. The science behind long exposure
Long exposure photography is used to capture images over a prolonged period of time, resulting in effects that are often not visible to the human eye in real time. The science behind it involves controlling the amount of light entering the camera by adjusting the key camera settings of shutter speed, aperture, and ISO—to create artistic images with motion blur, light trails, or to smooth water.
Key Settings
Shutter speed: Shutter speed refers to how long the camera's sensor is exposed to light. In long exposure photography, the shutter is left open for an extended period, ranging from a few seconds to several minutes or more. This allows the sensor to capture movement over time.
Aperture: The aperture is the size of the opening in the camera lens that controls how much light enters. A smaller aperture (higher f-stop) is typically used in long exposure photography to reduce the amount of light, especially during daylight, preventing overexposure during longer shutter speeds. Note that the aperture setting also affects the depth of field, with smaller aperture gives a larger depth of field, keeping more of the scene in focus.
ISO: ISO controls the camera sensor's sensitivity to light. In long exposure photography, a lower ISO setting is usually used in order to minimize noise in the image, particularly when the shutter is open for long periods. High ISO can introduce grain, which reduces image quality, especially in low-light situations.
Physics of Light and Motion Capture
When the shutter is open, the camera continuously records light hitting the sensor. If an object is moving, it will appear in multiple locations across the sensor during the exposure, creating a trail or blur. This effect is due to the additive nature of light - each moment of movement is added to the previous one, resulting in a smoothed or streaked appearance of the subject in the final image.
3. Essential Gear
Long exposure photography needs some specific gear to ensure you get the best results. Here's a list of essential items for long exposure shots:
Camera with Manual Mode
A DSLR or mirrorless camera that allows you to control the exposure time manually and have a "Bulb" mode for very long exposures (more than 30 seconds).
A sturdy Tripod
A stable tripod is essential for keeping the camera steady during long exposure shots. Any movement can ruin the image due to the extended exposure time. See this blog on tripods.
Neutral Density (ND) Filters
ND filters reduce the amount of light entering the lens, allowing you to extend your exposure time during bright conditions, such as daylight. They come in various strengths (e.g., 3-stop, 6-stop, 10-stop), and can even be stacked for greater light reduction. See this blog on ND filters.
Remote Shutter Release
Using a remote shutter release prevents camera shake when triggering the shutter. Some cameras have an app to control this wirelessly.
It is also possible to use the 2 second timer on your camera, so that the shutter doesn't open until you have moved your hand away (however, this will not work if you use "Bulb" mode to do exposures over 30 seconds.
Lens Hood
To minimize lens flare or prevent unwanted light from entering the lens during daytime shots, use a lens hood or something to block light sources.
Apps for Calculating Exposure Time
Use smartphone apps like "Exposure Calculator" to help you determine the correct exposure time when using ND filters.
Torch or Headlamp
If you're shooting in low-light or nighttime conditions, a small torch or headlamp is handy for adjusting settings or finding gear in the dark.
Final Words
Now that you understand what long exposure photography is all about, and you understand the basic equipment you will need to do it, next week we will look at a step by step guide to actually do some long exposure photography!
Want to improve your photography skills?
Don't forget that if you want some direct help with your photography, I offer a range of 1-2-1 photography courses for Devon based folks. If you're not nearby then I also offer residential weekends for beginners or improving photographers.
About me
I first got into photography after walking the beautiful South West Coast Path: I was so disappointed that my photos didn't do justice to the beautiful coastal scenery that I decided to walk all 630 miles all over again, but this time to also teach myself photography along the way!
A few years later and I find myself as a professional photographer, widely published and with landscape photos which have won national awards. But I do much more than landscapes, providing photography training to businesses & individuals on how to take beautiful photographs, and providing professional photography services to businesses across the South West. My commercial specialisms are property photography, business photography, people photography & aerial (drone) photography.
I’m also an author with a number of published books and I give regular talks about my passion for photography, and for Devon, to camera clubs and other groups.
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