Long exposure photography makes it possible to show the passage of time in a still photograph. It does this by blurring moving elements and sharpening the static parts. But there is a downside to long exposures – any camera movement blurs the static elements. Here are four simple ways you can prevent unwanted blurring.
1. Use a Good Tripod
For very short exposures there are ways to hold yourself and your camera steady, like: How to Reduce Camera Shake – 6 Techniques. However, when you’re taking an exposure of a few seconds, you need something steadier than your hands to hold your camera. You may set the camera on a table, or a rock but risk dropping the camera or accidental movement that can ruin your shoot.
The most common way is to put it on a sturdy tripod. You have to get at least a decent tripod as El Cheapo tripods are going to give you camera shake too.
2. Use a Remote Shutter Release
Even with a tripod the act of snapping the shutter can cause the camera to shake. There are a couple of ways to combat this problem.
One is to set the delay on the camera (2-sec timer) so any movement is done by the time the shutter snaps. The other is to get a remote shutter release.
Remotes can be connected to the camera by a cable or wireless – either one snaps the shutter without shaking the camera. They are also called remote cable releases. This is a small and cheap accessory which can help you get rid of camera shake.
3. Use Manual Focus
Autofocus is a wonderful thing. Most of the time it does exactly what you want, making it easier to take great photos. But there are times, especially when shooting long exposure, that it can have the opposite effect.
In low light situations autofocus has trouble finding something to focus on. Even when it seems focused it can readjust when the shutter is snapped. Using ND filters can cause the same problem.
Fortunately, there is a simple solution. When shooting in low light you can use manual focus, or use a flashlight for focusing and once the focus is set, turn autofocus off so it won’t change once the light is off.
For ND filters set the focus manually (either before or after mounting the filter) or autofocus first, turn it off and mount the filter. The shot will stay focused, the picture sharp.
4. Lock the Mirror Up
If you are using a DSLR camera – and you probably are since you are shooting long exposure – it has a mirror that reflects the image from the lens to the viewfinder. It is between the lens and the camera sensor, so it has to move before the shutter snaps.
That small movement causes vibration. When you turn on the mirror lockup it turns the shutter button into a two stage button. The first click lifts the mirror and the shutter doesn’t open until the second click. The time between the two clicks allows the vibration of the moving mirror to stop.
5. Use Your Aperture Sweet Spot
Closing down the aperture can make you shoot longer. However, when your aperture is too small, it will start to have a diffraction effect which lowers the sharpness.
In most lenses, the sweet spot of the lens aperture is between f/5.6 to f/8. In other words, you will get the sharpest images when using this range.
When you step down to f/16 or smaller, you will get images like that seem out of focus. You can learn the physics about diffraction in the below video by Steve Perry:
Taking long exposure photographs is a science and an art. Like any art, taking long exposure pictures with the right balance of sharpness and blur takes both skill and intuition. These five tools will help you use your skills to turn intuition into great photographs.