Saturday, November 9, 2013

Make the Shot: Slow Sync Photography

A "slow sync" photograph is one where the length of the shutter speed is longer than that normally used with a flash (either external or on-camera). This allows more visibility for background objects or dimmer lights and can have many creative applications. This post will talk through the process behind making this shot using slow sync:
Slow Sync Apple Cutting - straight out of the camera (SOOC)

The shot above was created using a single exposure and without any digital manipulation. The critical elements of making this shot or a similar one is the use of slow sync and second curtain flash.

Second curtain flash means that the flash will fire at the end of the exposure, rather than at the beginning. Dig around within the settings on your camera, and you will find an option to choose second curtain. (On my Canon T1i, it is under flash control, built-in flash function setting, and shutter sync.)

In order to set a longer shutter speed and use the flash, you will need to use the manual shooting mode on your camera. Keep your ISO low (100 or 200) and use a wide aperture to maximize the amount of light gathered from the background during the portion of the exposure before the flash. The speed you select for your shutter will depend on the amount of time it takes for whatever movements or effects you want to try. The final settings for the image above were ISO 100, f/5.6, and 20-seconds.
Wide view of the set up for this shot (before turning the lights off)

The setup for the final shot was fairly simple: I needed an apple, a knife, and a cutting board. My end table / sewing machine acted as a stand-in for a wooden table, and a sheet strung up between the two curtain rods acted as a backdrop. I deliberately placed the end table a little distance away from the backdrop so that the backdrop would be outside the plane of focus.

Because I suspected that it would take me several efforts to nail the timing and get the shots of the knife spaced out the way I had envisioned them, I knew that I did not want to be trying to actually cutting the apple during the photograph. An extra touch of realism could be added by cutting the apple in half before and finding a way to keep both halves upright and slightly separated with room for the knife to move through.
Sample composition set up shot, taken with surrounding lights on

After getting all the parts in place, I set my camera up on the tripod and zoomed in to establish the composition I wanted. I used the apple to set the focus while all the lights were still on and then switched the focus to manual to keep it fixed at the apple. The 10-second countdown timer on my camera gave me enough time to start the countdown and get into place before the exposure started. I also turned off all of the lights around the set up, leaving on just the lights in the hall behind the camera.


Moving the knife smoothly through the entire exposure resulted in the picture above. (The astute among you may notice that I also had not finished moving the knife when the flash fired and the camera stopped taking the photograph.) While this smear effect has a lot of interesting applications, it was not the look I wanted for this particular image.

The real trick behind this kind of shot is in the timing. In order to have the knife visible in each of the different locations, I figured out that I had to hold it in place for about 3 seconds in each spot before quickly moving it down to the next position and holding. When the knife made it to the bottom, behind the apple, then the exposure would finish and the flash would fire, illuminating the apple, cutting board, and background.


There are lots of creative applications of slow sync photography and second curtain flash. This technique is particularly applicable to creating ghostly images by moving slowly or partially during the final exposure. Give it a try, and see what you can create!
Ghostly Book Filing

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