Have you ever seen landscape images where the water looks soft, silky and smooth? Or perhaps an image showing lines of light traversing through a city scene?
Then you’ve seen long exposure photography. It’s easy to create and doesn’t need heavy manipulation. In this article, we’ll show you how to do it yourself.
What Is Long Exposure Photography
There are many ways we can use this technique to achieve different results. Not only will it turn water into a smooth surface, it can also help remove people from a scene or situation.
Any moving element is obscured when using a long shutter speed. There is no limit to where you can use this technique. Any genre of photography can incorporate a long exposure, even time-lapses work well.
I like to use long exposure in street photography as it shows the hustle and bustle of a scene. All this without blurring the environment.
Craig Hull – craighullphotography.co.uk
How Does Shutter Speed Affect Long Exposure Photography
The shutter speed is fundamental to photography. To capture an image, our camera uses three things; ISO, aperture and shutter speed. ISO looks at the quality of the image, aperture affects the depth of field, and the shutter speed affects motion.
All three of these make up the exposure triangle.
The shutter speed comes in fractions of seconds. Typically, you will be working from a range of about 1/125 – 1/500 for everyday photography. Here, 1/125 means the shutter is open for one 250th of a second.
If you divide one second into 250 equal parts, this shutter opening would equate to just one of those parts. One complete second on your camera would look like this: 1″.
A fast shutter speed (1/1000+) freezes subjects that move very fast. Anything below 1/30 might is a slow shutter speed. The range is usually 30″ on the slowest side all the way to 1/8000 to the fastest.
There is a limit to what shutter speeds we can use without a tripod. Anything below or slower than 1/60th will show signs of camera or mirror shake, becoming more extreme the slower the speed.
This is down to the shutter being open for a long enough time to pick up on small vibrations.
Another factor to consider is that longer focal lengths will exemplify the amount of camera shake. Some lenses (telephoto) have image stabilisation built-in.
The rule of thumb is to use a shutter speed that has a higher denominator than the lens. A 100mm lens will need a minimum shutter speed of 1/125.
What Gear Do You Need
To create a long exposure shot, we will need some equipment.
A tripod is essential for long exposure photography. As I pointed out, anything below 1/60th of a second will create blurriness in your images. Long exposures tend to create photographs from exposures as long as 30 seconds, some could even take hours.
Holing a camera for 30″ would produce an immense amount of camera shake. That is if you can even hold your camera for that long without your arms failing. A tripod makes your life easier and ensures a sharp, clean image.
Tripods are inexpensive but get something sturdy that will survive a few bumps. We recommend the 3 Legged Thing Punks Corey Aluminum Tripod as it is lightweight and folds up small. Perfect for traipsing across the countryside or city.
A shutter release is a helpful piece of equipment. We talked about camera shake due to handholding the camera, but even pressing the shutter button can cause blurriness.
These releases come in two forms; one that connects to your camera via a cable, and the other via infrared. The wireless version is a little more expensive, but it means you don’t need to be next to your camera to operate it.
If you already own an intervalometer from capturing time-lapse photography, you can use it here as a simple release. The other option is to change your camera settings.
Setting the mirror to ‘lock-up’ before your shot will reduce the shake. Also, setting your camera on a two-second timer will help.
A neutral density filter is an invaluable piece of equipment allowing you to capture long exposures. They limit the amount of light that enters the camera lens, hitting the sensor. These are items you would use in the daytime.
The abundance of light makes it impossible to capture a correct exposure while capturing a long exposure.
These come in different sizes, namely 2 Stop, 6 Stop and 10 Stop. The numbers are the different strengths of the filter. The amount of stops tells how much you can increase the shutter speed.
The 6 stop filter is stronger than the 2 stop, yet not as strong as the 10 stop filter. Each ‘stop’ of an ND filter reduces the amount of light entering the camera by a factor of 2.
1 stop = 21 = 2 = ND2
2 stops = 22 = 4 = ND4
3 stops = 23 = 8 = ND8
4 stops = 24 = 16 = ND16
5 stops = 25 = 32 = ND32
8 stops = 26 = 256 = ND256
10 stops = 210 = 1024 = ND1024
A fairly common 2-stop filter (ND4) reduces the amount of light hitting the sensor by a factor of 4. A 3-stop (ND8) filter by a factor of 8 and so on.
A 10-stop filter reduces the light by a factor of 1024, meaning that the shutter needs to be open for over 1000x longer.
For example, a photograph that would normally be taken at a shutter speed of 1/1000th of a second becomes a one-second exposure.
Tips for Using Filters
A tripod is necessary for long exposures. It is even more important when photographing a scene with a 10-stop ND filter. Exposures with this filter will turn into minutes.
Close your viewfinder shutter (if your camera has one) to ensure correct light metering.
Use ‘bulb’ mode on your camera as it will allow you to capture the scene for as long as you want. Using the shutter speed on a manual setting will give you a maximum of 30″. Here, you will need a shutter release cable.
Make sure you choose the right conditions. If there are no moving elements in the scene, you don’t need to use a long exposure. Remember – the long exposure effects and obscures the moving elements.
Even using a low ISO can create noise from super long exposures. To remedy this, take the exact same picture, with the same settings, but with the lens cap on. This method will produce a black image, but will also pinpoint the hot pixels. Use this as a guide to eliminate them during post-processing.
Some ND filters leave a colour cast. This is even truer when dealing with filter ‘stacking’ or using welders glass as a cheap alternative. The majority of the colour can be corrected in post-processing, but sometimes, a black and white conversion is the only way to go.
Do not use a long exposure to cover up a bad composition. It will amplify the problems and the time it will take you to try and fix them.
How to Get Started With Long Exposure Photography
As we have covered the gear, ND filters and tips, we can now get started. This technique will work in many different scenarios. And it’s basically the same for every different type of photography.
If you are looking to capture the sky and sea, don’t go for 50/50. What am I photographing? This should be the main question. A long exposure is used to enhance your image.
It won’t turn a bad composition into something good.
Make sure your camera settings are correct. Keep your ISO on 100, use a medium aperture to keep the scene in focus and change the shutter speed accordingly. Utilise the ‘bulb’ mode for exposures longer than 30″.
You need to be photographing in RAW. This allows more play in post editing your image.
Using your ND filter to cut out light will work for photographing a scene, but it won’t help much with focusing the scene. What you see in your live view or viewfinder will be too dark.
Set your focus without the filter, and switch to manual focusing to ensure you don’t change it.
Take a test shot and look it over by zooming into the image. This will allow you to fix any errors before proceeding to capture a 30-minute exposure.
Taking the Shot
Now you’re ready to go. The only thing missing are the calculations for the long exposure. How long should the exposure be? This is the most difficult aspect of this type of photography.
After a while, you will be able to tell what exposure you need based on the light you can see.
There are two ways of calculating the exposure times, and both will give you the same result. Learning the harder technique will help you understand how we get to the final exposure time.
There are tools that will help you in making your long exposure photography easier. For smartphones, there is an application called NDCalc. This will calculate the correct shutter speed based on the shutter speed you need without a filter.
This application will even give you a timer, letting you know when to end the exposure. Ok, this is the easier way, now it’s time for the harder route.
If you use a 10-stop ND filter, there is 1,000 times less light reaching your camera sensor. This means that you need to lengthen your shutter speed by 1,000.
So, if you use a shutter speed of 1/30, it extends to 32 seconds. 1/125 will become 8 seconds.
And there you have it. Get out there and start practising. Try, try and try again until it becomes perfect. Monitor your first exposure, and change the shutter speed according to the photograph.
Before you go, look at this awesome long exposure photography video.
A note from Josh, ExpertPhotography's Photographer-In-Chief:
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