A long exposure creates interesting effects
Using a long exposure allows you to pick up subtle lighting, photograph fireworks and create light trails. It also allows you to go into dark environments and photograph without disturbing those around you.
When to use a long exposure
A long exposure can help you capture subtle light. It is very effective when your subject is lit in a darken area. For example, fireworks against a night sky, the trail of headlights a passing car makes at night or when you are photographing in a darken room where the focal image is well lit.
Here is an example of using a long exposure to capture the subject and retain the mood of the room. This globe was actually a blank screen in a darkened room with images projected upon it. By turning off my flash and using a long exposure I was able to capture this image, retain the mood of the room, and not disturb the other guests viewing the show.
This photo of light trails is an example of using a long exposure to create in interesting effect. In this photograph I wanted to capture the light patterns these hula hoops created when they were spun in the air. By using a long exposure the camera captured the light pattern created by the hula hoop dancer that couldn’t be seen by the naked eye.
How to set shutter speed
The way to set a long exposure depends on the type of camera you have. Let’s look at each type.
Long exposure with a DSLR or any camera where you can set the shutter speed
If you have a DSLR, mirrorless or compact camera where you can set a specific shooting mode, set your camera to either manual or shutter priority. You have this type of camera if there is a dial on it with an Tv or S as one of the options. Selecting S or Tv on the dial puts the camera into shutter priority. Read the manual for your specific camera to learn how to set shutter priority on your specific camera. They are all a bit different. With most cameras you simply turn the dial so S or Tv is near the selection arrow.
Shutter priority means that you set the shutter speed you want to use and your camera will automatically determine the aperture needed for the correct exposure given the ISO you have chosen. If you are new to this, then start out in shutter priority rather than manual. With manual you have to determine both the aperture and shutter speed, so it’s easier to use shutter priority.
The last step is to select the shutter speed you need for your situation. More on selecting the right shutter speed for the situation later.
Long exposure with a point and shoot camera
If you have a point and shoot camera you might be able to achieve a long exposure effect. For point and shoot cameras it depends on the settings available to you. Most cameras have a way to turn off your flash. By turning off your flash you will force your camera to select a longer exposure (and a higher ISO too). This works well when you just need a bit longer exposure like my globe example.
Nighttime mode is a common feature in point and shoot cameras. Designed to photograph city lights at night, it would be a good setting to use when photographing the globe.
Many point and shoot cameras have a fireworks mode. This will set your camera up to do a longer exposure and would be the mode I would use for situations like the hula hoop dancers.
What are ISO and shutter speed?
ISO is the level of sensitivity your camera has to available light. The part of your camera that is responsible for gathering light is called the image sensor. As you change the ISO setting, the image sensor in your camera will change the way it gathers light. The lower the ISO number the less sensitive your camera is to light. The higher the ISO number the more sensitive your camera is to light.
Higher sensitivity to light comes at a price. The higher you set the ISO the more noise you’ll see in your photo, so in general a lower ISO setting is recommended. Most cameras these days shoot fairly noise free up to 1600 or 3200 ISO, but it’s recommended to use the lowest ISO possible to get the best image.
When you press the shutter button on your camera the aperture in your camera lens will open. How long the aperture stays open is called your shutter speed. The longer it is open, the more light will hit your camera’s image sensor. Most people can only hold a camera still for about 1/60th of a second, so in general shutter speeds are set to 1/60th of a second or faster.
How are ISO and shutter speed related?
They are a trade off. The higher you set the ISO the less light you need on the image sensor, which means the shorter your shutter speed can be. But remember the higher you set your ISO the more noise you’ll have. A higher ISO will allow you to shoot in lower light situations. The higher the ISO the faster your shutter speed can be and vice versa.
If you are shooting in shutter priority, then you are allowing your camera to select the aperture setting. However if you are shooting in manual mode, then you will also need to consider the aperture setting you choose. As the focus of this article is shooting with long exposures using shutter priority, I will only mention this briefly so that you are aware that the aperture you select also plays a factor. The aperture setting refers to how big the opening is when you click the shutter button to take a photo. The smaller the f-stop number is, the larger the opening will be when you click the shutter button. As you can imagine the larger the opening the faster light comes in, so with a small f-stop (large opening) you can use a shorter shutter speed and lower ISO. And of course your f-stop setting determines your depth of field (how much is in focus). You can read more about aperture settings and depth of field here.
What is a long exposure and how do I choose how long to set it?
In general a long exposure is a shutter speed set to longer than normal. It is sometimes referred to as a slow shutter speed, meaning the shutter is open for a long time. To me a shutter speed setting longer than 1/30th of a second is a long exposure. It is always best to place your camera on a tripod when using a long exposure, as it’s virtually impossible to hold a camera steady long enough to capture a crisp image without one. A remote trigger is also useful to reduce camera movement when you press the shutter button.
I select the length of the shutter speed based on the available light and the effect I want in the final image. Let’s look at a couple of examples.
For this photo I did not have a tripod with me, nor was I in an environment where one could be set up, so I choose to use a high ISO (3200) setting on my camera. ISO refers to how sensitive your camera is to absorbing light. The higher the ISO the less available light you must have to get the image. With a high ISO I could use a faster shutter speed to photograph the globe. The room was dark, so even with ISO set to 3200 I needed a 1/6th of a second shutter speed to obtain the proper exposure for this image.
You will notice that the globe is slightly blurry, as even with my arms tucked closely to my body and holding my breath I can’t hand hold a camera steady for 1/6th of a second. For purposes of remembering this show about the earth I’m okay with the blur. My choices were to take a slightly blurry image using a high ISO and slow shutter speed, or using a flash which would have disturbed the others in the room and given me a very different photo loosing the mood of the show. For me a slightly out of focus image was the best option.
There are 2 ways I could have accomplished my goal of capturing the image of the globe. One was to shoot in aperture priority selecting the depth of field I wanted, select a high ISO (3200) and let the camera determine the shutter speed. The other was to set the longest shutter speed I wanted to use (1/6th of a second), the highest ISO I wanted to use (3200) and then let the camera determine the aperture. Both are viable alternatives.
For the globe photo, if I had a point and shoot camera I would have turned off the flash and selected a nighttime setting. This setting is for capturing city lights at night and would have worked well for the globe photo.
This image of hula hoop dancers is a very different case. Here I wanted to use a long exposure to capture the light patterns of the hula hoop as it was spun by the dancer. The easiest way to capture these light trails was to set a long shutter speed. Again I was without a tripod, so I tucked my arms close to my body to steady the camera as best I could. A very long shutter speed was used to capture the light pattern that emerged as the dancer moved the hoop in a full circle. For this image I used a lower ISO (800), because I needed a 0.4 second shutter time to capture a full circle of the dancer’s movement. Using a 0.4 second shutter speed allowed me to capture the wonderful light pattern the spinning hoop made.
With a point and shoot camera, I would have used the fireworks setting on my camera. Fireworks also create light trails, so that setting should have worked well here.
From these two examples you can see how ISO and shutter speed are related. When you want to capture movement, use a longer shutter speed timed to the movement you want to capture and the corresponding ISO to get the correct exposure. When photographing in a dark place, select a higher ISO and a shutter speed to give you the correct exposure.
Favorite Photograph Tools and Resources
You can find a list of my favorite photography tools and resources here.
Photographing in dark places can produce some fun effects. Hope you give using a long exposure a try. Happy Scrapping!