The Magic of Slow Shutter Speeds
We often spend so much time making sure that our shutter speeds are fast enough to avoid camera shake or blur from movement, that it might sound odd to talk about improving your photos by slowing down the shutter speed. But that’s exactly what we’re going to do.
Why would you do this? Because certain photos can be improved drastically by using a slower shutter speed. In fact, some photos can be transformed entirely. Think about using a slow shutter speed when you have moving water or clouds in your picture. You can create a nice blur to these parts of the image, while other parts of the image will remain steady to anchor the image.
What You Will Need
The good news regarding working with slow shutter speeds is that you probably already have most of the equipment you need. Besides the camera, all that is required is a tripod and remote shutter release.
You might need a neutral density filter though. That is a filter that restricts the amount of light that is allowed into the lens. When you attach this filter, it reduces the amount of light coming into your camera so that you can use a longer shutter speed without overexposing your image. They come in a variety of strengths, which are measured in “stops” of light. Get the 10-stop version, which is strong enough to have a pronounced effect on your images.
How Slow is Slow Enough?
Before we get started, how slow does the shutter speed need to be? Unfortunately, I cannot give you a clear answer to that question. When it comes to making clouds move in the sky, there is very little guidance I can give you because clouds are always moving a different speeds. You will need to use a shutter speed of at least 30 seconds, usually over a minute. Sometimes you will need a shutter speed that is several minutes long.
When it comes to water, however, I can offer you a little bit of guidance. Try working with these ranges:
- To create a slight blur to create a sense of movement: use a shutter speed of 1/8 – 1/2 seconds.
- For completely blurred water: use a shutter speed of 15 – 30 seconds.
- To smooth out the water entirely: use a shutter speed that is 30 seconds or longer.
Of course, the ultimate speed will depend on the exact effect you are looking for and the conditions you face. Don’t be afraid to experiment.
“Slowing down the water just a bit can create a sense of movement. Here, closing the aperture to f/16 and reducing the ISO to 100 allowed me to use a shutter speed of 1/5 of a second, which created the slight blur I wanted.”
How to Take the Slow Shutter Speed Image
When you are ready to take the image with a slow shutter speed, you first need to place your camera on the tripod and set up your composition. Attach the remote shutter release. Get the picture ready to go without even thinking about exposure yet.
When that is ready to go, it is time to set the exposure to achieve the slower shutter speed you want. What we will do here is make a series of changes with one goal in mind – increasing the amount of light needed to properly expose an image so that the camera can use a long shutter speed without overexposing the image. Here are the steps for doing so:
- Manual Mode: Put the camera in manual mode (unless your shutter speed will be longer than 30 seconds, in which case use Bulb mode). You will find that manual mode is the easiest to work with in this context. Plus, you will be working slowly, so there is no need for the speed that the other modes provide.
- Reduce the ISO: Set your ISO at its lowest native setting. In most cases, this will be ISO 100. When you use this setting, your camera’s digital sensor is the least sensitive to light. That means that more light will be needed to properly expose the image.
- Stop Down the Aperture: Set your aperture at its smallest setting. The aperture is the hole in the back of the lens that allows light into the camera, and making it smaller restricts the amount of light being allowed into the camera during the exposure (again, with the idea of forcing a long shutter speed to get a proper exposure). The aperture setting is the number with the f/ in front of it. The smallest setting is actually the largest number. The number varies depending on the lens you are using, but typically the smallest aperture setting will be in the neighborhood of f/22 – f/32. (If you are worried about the effects of diffraction, perhaps use the next smallest setting).
- Set the Shutter Speed: Now just set your shutter speed to the proper exposure level using the camera’s meter. The changes you made to the aperture and ISO should result in a slow shutter speed.
Is the shutter speed slow enough for you? If so, go ahead and take the picture.
“Before and after of the Portland Head Light in Maine. The picture to the left was taken with a shutter speed of 1/320 of a second. I put my 10-stop ND filter on my lens and took the one to the right with a 4 second shutter speed.”
Making the Shutter Speed Even Slower
If the shutter speed is not slow enough for you, then you will need to break out the heavy artillery. By that I mean it is time to attach the 10-stop neutral density (ND) filter. This will greatly restrict the amount of light allowed into your camera so that you can use an extremely long shutter speed.
“For completely blurred water: use a shutter speed of 15 – 30 seconds.”
A 10-stop ND is so dark that you will not be able to see through it – and neither will your camera. Your autofocus won’t work, so you will need to set the camera’s focus before you attach the filter. The camera’s light meter might not work either. If that is the case, set your exposure before you attach the filter, then increase (lengthen) your shutter speed by 10 stops. That will be 30 clicks of the dial if your camera is set to change in 1/3 stop increments (which most are).
That should allow you to use as long of a shutter speed as you want. In fact, sometimes it is a little too long. In that case, just increase the ISO or open up the aperture a little bit.
Apply Long Exposures to Your Photography
That’s all you need to know to go out and add some magic to your photos by using long exposures. This technique can greatly improve pictures in a variety of settings, but where it really shines is when there are moving clouds and water in your picture. You can also use it to create the “streaking lights” effect you see with traffic. This might be the missing “extra something” that your photos have needed!