Special Effect – How to Create Multiple Flash Exposures in a Single Frame
Many photographic techniques, rightfully, tend to focus on polished images. They vary anywhere on the spectrum from getting sharper images to capturing accurate skin tones. These techniques are important. However, sometimes they’re not very much fun. Sometimes, that’s precisely what you need to have, and exactly what photography should be – fun.
This article will guide you through a fun special effect technique that will allow you to capture multiple exposures in a single frame, using the test button on your strobes or flashguns. Using this method, you will gain a new tool to add movement, and a sense of action in your studio photography.
What you need
- A dSLR on manual settings (set from 2-10″ or bulb exposure)
- A very dark room (or nighttime outdoors)
- A tripod
- A human subject
- A strobe or flashgun (speedlight) with a test button (to manually fire the flash)
- Someone to serve as an extra pair of hands (not required but it helps a lot)
Setting it up
Because you’re using flash, the aperture setting is the most important in this technique. As long as your shutter speed is slower than your camera’s flash sync-speed, aperture is what controls how the flash exposure is recorded, and it also dictates what power output to set on your flash. I suggest using an aperture somewhere between f/8 and f/16, to get the best results. A smaller aperture will also help to minimize the effect of any ambient light in your images.
With your camera on a tripod, set the dial to manual mode, the ISO to 100, and your shutter speed to between two and six seconds. To test if your shutter speed is suitable, take a test shot without any flash. As long as the image is completely black at the end of the exposure, it will work for this technique.
This time can be changed and extended later, depending on how many movements you want to capture.
To start with, try to keep your lighting simple. A single light source will give you unlimited potential. This technique will work with multiple lights, but it is best to build up to that over time, as you get used to how the technique works.
As for lighting placement, the choice is yours. The lighting will, and should, depend on the final intent of the image you are trying to create. However, if you’re unsure, try starting with your light high above, and in front of, your subject. That will provide a good starting point to make adjustments from there.
Use a light meter, or manually calculate the exposure, to set your flash output, so it matches your chosen aperture.
Simple lighting set-ups, like this one used in these images, can be the most effective.
With everything set up, you need to explain to your subject how to move. The easiest way to explain this is, “Pose, wait for the flash, pose, wait for the flash, and pose again”.
In more detail – you want to wait for your subject to adopt the first pose, set the focal point, and start the exposure. Press the test button on your strobe to fire the flash. After this first flash, your subject should move to their second position as quickly as possible, where you will press the test button again. Repeat as many times as required.
The hardest part of this technique is that it is incredibly hit and miss. Getting your subject to move into positions that create pleasing compositions, without be able to evaluate while it’s happening, is tricky. It takes time and patience. You will need to shoot a lot of frames, and most of them will be unsuitable. Just keeping making as many attempts as you can, until you think you have something, then take some more.
Here are a few things to keep in mind that will make your attempts easier.
Sometimes it’s hard judge how movements will appear in the final image. By trying to squeeze too much in, you might end up with a cluttered mess in your images. Start with two or three movements to gauge where things are and build it up from there.
Trying to include too many movements may result in a cluttered mess like this image.
If you have a remote trigger for your strobes with a manual button on it, you can hold it in your hand and fire the flash. This is much more preferable than having to move between the camera and your light source during each frame.
If you want to squeeze more than two or three movements into a six second exposure, try to ensure that your flash isn’t set to full power. By reducing the power output, you’re also decreasing the amount of time it takes your flash to refresh. This will allow you to fire the strobe more times in the short timeframe.
There is no one way to process images from this technique, and all of that is up to you. However, if you want crisper, more pronounced outlines of your subject, the clarity slider in Lightroom or Adobe Camera RAW will help a lot.
Colored backdrops will overpower images using this technique.
For color images, try and stick to a black or grey background. Because your subject is moving to different positions, the background continues to expose once your subject has moved. If you use a colored background, as I did with these images, that color will dominate your exposures. Of course, this can be used judiciously as a feature of the image should you choose.
Two second timer
If you can’t rope someone into being your assistant for the day, set your camera to use the two second timer, to give you time to move between the camera and the strobe.
Once you’ve had a go at this technique with people, feel free to try and think of ways to use it with other subjects. For example you could use it to capture a hammer at different points in its swing, or perhaps a basketball at different parts of its arc. The choices are endless. Be creative with it, have fun, and if you give it a go please share your images below, as well as any questions you may have.
This is the third of a series of articles we will be featuring this week on dPS all about special effects. Check out the others here:
- How to Photograph the Full Band of the Milky Way
- Fire Spinning with Steel Wool – A Special Effects Tutorial
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