Sometime you have a scene that has stuff that keeps moving through it, marring the picture you are trying to capture. Falling leaves, rain, snow, even people can be removed by taking a longer exposure. The length of exposure will vary, depending on what you are trying to remove. Rain may disappear with a 1/15 second exposure. Snow, being brighter, may require a 1/4 second exposure or longer. Leaves, being slower and larger, may take a 1 second exposure to leave no trace on the photo. People are harder. If they are moving slowly, stop frequently, or there are just a lot of them, then you may never be able to get rid of them. On the other hand, if you have a scene that just has a couple people in it who keep moving, then you may be able to take a 15- or 30-second exposure and they will virtually disappear! This technique requires a tripod or other stabilization method. You will also benefit from having a neutral-density filter to reduce the light coming into the camera, which will allow you to use a slower shutter speed. For an exposure less than a couple of seconds in time, you should use the self-timer or a remote release to trigger your camera, as the camera shake due to your pressing the release button may be enough and last for such a significant portion of the exposure that it causes some blur in the picture. The larger the object you want to “remove”, the longer the shutter speed must be. You might need a neutral-density filter to dim the incoming light so that you can obtain very slow shutter speeds. Moving objects such as rain, snow, or leaves can be eliminated by using a ½ second shutter speed, while passing tourists may require 10-15 seconds so that they don’t register. Of course, any object that doesn’t move for a significant portion of the shutter time will appear in the final image. Your camera must be on a tripod or otherwise immobilized for this technique.
You can also use this technique to perform in-camera double exposures.
- Focus on a couch and set your camera for at least a five-second exposure. You may need a fairly dim room to achieve this slow a shutter speed. Make sure your ISO is set to the lowest number possible. Use the self-timer or remote control to trigger your exposure. Sit on one side of the couch for half the exposure time, then quickly shift to the other side of the couch. Two ghost images of you will appear.
- Select the slowest shutter speed you can; you might want to do this in dim light or using a neutral density filter to allow a longer shutter time. Cut up a piece of paper into small pieces, or use a hole-punch to get a bunch of small punch circles. Focus on your subject (you might need to use a flashlight on your subject to get enough light to focus with) and then click the shutter and let the small pieces of paper flutter down in front of your subject. If your shutter speed is greater than a couple of seconds, you will likely not see the paper that fell through the scene.
- Set up your camera in a dim room or outside in the evening, when your shutter speed will be in the 10-15 second range (you could also use a strong neutral density filter if you have one). Focus on your subject (you may need to use a flashlight to illuminate your subject for the camera to be able to lock focus), then put your camera into manual focus mode. Click the shutter and then walk back and forth through the scene at a normal pace (do not walk towards and away from the camera, but rather across the scene). When the photo is complete, you should see that your passing across the scene was not visible in the image – you were effectively invisible.