What is Slow Sync Flash – How it’s Done and How it Works

If you enjoy experimental photography you will definitely want to explore your options with something known as “slow sync flash”. This is actually a setting on many modern digital cameras that forces the camera to shoot using a long shutter speed while it also fires the flash.

Interestingly enough, there are a few ways that slow sync flash can work, especially for those with feature-rich cameras. For example, the image above relied on the setting within the feature known as the “front curtain” sync. This is when the photographer wants to use the slow sync feature, but also wishes to control the point at which the flash actually fires. When it is the front curtain setting it fires the flash at the beginning of the exposure and leaves the shutter open for a brief period afterward. In the image above we can see that the ambient light of the street scene has allowed a ghost image of the subject to be recorded after the flash.

We can also notice that the photographer opted to hand-hold the camera, which is evidenced by the blurring of the street lights and some of the immobile fixtures in the background. Is this recommended? Actually, the slow shutter speed might automatically make the photographer feel that hand-holding the camera is out of the question, but that is not always the case. The movement and blur created by the slow sync feature might be greatly enhanced through the introduction of camera shake too. It is a good idea to experiment a bit with the various techniques to see which generate the best results.
In addition to the front curtain option, there is also the “rear curtain” sync as well. As might be expected, this setting fires the flash at the very end of the exposure. This allows only ambient light into the camera for the initial segment of the exposure, and then freezes movement with the use of the flash right before the shutter closes. This is a wonderful way to capture trails of movement behind objects before illuminating them with the flash.
So, what are some examples of moments when the slow sync shutter technique could be used? Parties are a common time for this feature because it creates tons of light and movement in the scene. Many amateur and professional photographers head to concerts to use the slow sync flash for some really impressive results. There are plenty of commercial applications for it, and those who enjoy the “painting with light” techniques will find that the front and rear curtain techniques are well worth a bit of experimentation. It can also be used to give a “rock star” or paparazzi look to standard portrait photography, and will also be capable of rendering standard portraits in innovative and unique ways.
For example, why not use the rear curtain technique on a subject who remains still, but who is situated next to a moving object. For example, stand the subject against a streetlamp or tree that is located close to a busy street. Make sure that you are shooting in the evening hours in order to make the background full of color and movement. Wait for a bus or larger vehicle to approach and as it passes shoot the image. Your subject will have the appearance of standing in a full spotlight while the background is a blur of movement and light.
A very popular thing to do with the slow sync setting is to make motion trails and paintings with light. For example, position the camera on a tripod in order to prevent any sort of shake and then aim it at a blank wall or a solid object such as a table. Now, position your subject so that their lower arm and hand fill the frame. Ask them to move their hand in a swiping motion in front of the lens. Do this to determine the path of motion that keeps them in full sight of the lens, and also to figure out how long it will take them to move from one side of the image frame to the other. Now, place something like a playing card or other colorful object in their hand. Using the rear curtain setting, trigger the shutter and have them slowly move their hand until the shutter fires and the lens closes.
What you will have is a very clear trail of movement captured in the surrounding ambient light, and then you will have a crystal-clear image of the arm holding the object. This is something that often looks like animation or illustration rather than a photograph, and is only one example of the many opportunities available through the use of the slow sync setting.

Photo by Daniel Garde.


About the Author

Amy is an multi-award winning photographer from Australia. She teaches enthusiast photographers how to take beautiful, professional photos in easy, plain English. She has a monthly photography emagazine and ebooks to help you create stunning images every time.

Comments (8)

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  1. Lance says:

    I like that photo. Its welldone.

  2. Shane says:

    Thanks good article.

  3. Mark says:

    I think this is a tricky method to do, it’s hard and I can never get it quite right.

  4. Abdullah says:

    many thanking you for good article.

  5. Luki says:

    That is amazing Amy, thank you. I have always wondered how to do this technique, now I know. I love the streaky look and will try this at a party I am going to this weekend.

  6. kate says:

    Slow Sync Flash is a very interesting technique. Thanks for a great article Amy! Love your Ezine by the way, it’s excellent. :)

  7. Mandy says:

    Thanks Amy, great article.

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