What is Slow Sync and how can I do it?

With so many photography terms used to describe certain techniques and tricks, it’s hard to know how to navigate and learn new skills. I hope today’s How To Tuesday can dispel some of the myths behind one of the coolest, and easiest photography techniques out there. Slow sync refers to using a slow shutter speed in conjunction with firing your camera flash, usually is low ambient light situations. You will often see websites talking about Rear Sync, and Rear Curtain Sync. These are features that alot of newer Digital SLR, point and shoots, and even older cameras have as an auto feature. Here I will tell you how to manually do this yourself, taking the guesswork out of the process and allowing you to use the Slow Sync Flash method in many situations!

Breaking down slow sync, what does it mean?

Slow is describing the slow (or longer) amount of time the shutter is left open and Sync is describing the flash firing during the time the shutter is open, allowing the light to sync with the shutter and then expose on your camera sensor. Combine those two features, and what you have is a longer shutter speed exposing in lower light situations, sometimes creating motion, and your flash exposing your subject oftentimes “freezing” it amongst the moving backgrounds. 

Using the slow sync technique, you can create stylistic “movement” in your images which can showcase an even more intimate depth to your image and subject story. As I have always said, we are telling stories of our subject in a 2D world while they exist in 3D. How do we create depth where there is none? Creating depth is easy with using shallow depth of field by selecting wider apertures (lower aperture numbers) and select rules of composition like Converging Lines. Slow sync with flash is another great way to create that depth.

What do I set my camera to for slow sync?

While every situation will be different, you can take these steps to work towards success. As with any experimentation with a new photography technique you must use the advantage you have: image playback! Make sure you set your camera to show your exposure (Canon: Info, Nikon: display) so you can make the adjustments to shutter and aperture independently. 

First you must be in Manual Exposure so you can set your ISO, aperture, and shutter speed independently. Make sure you are in an environment with a background that’s interesting, but not too bright. You want to be shooting at twilight, dusk, or a low lit situation. Your background MUST be subtly brighter than the light on your subject. These scenes are found at night outdoor weddings. sunsets, and like my rooftop scene of Peyton. Start by setting your ISO to 800, set your shutter speed to 1″ (one second) and your aperture wide open to the widest aperture available. I like to start here because when I take the photo, I can then dissect what is wrong, and just change ONE variable (shutter, f-stop, etc…). I usually start with my flash on manual settings, and at 1/8th power. 

I set my auto focus point to the middle spot focus, that being the most effective one in low light situations.

PRO TIP: if your subject is right in front of you, select the default Auto Focus mode which selects the “closest object” and is very effective in low light!

Here I will do a test shot:

If my subject is too bright and over exposed, I’ll turn down the power of my flash and do another test shot until i get it right.

If my background is too dark i will open up my shutter to longer, like 2″ and do a test shot. If I find my subject is getting blurry, then that means I need to increase my ISO. This way our background is going to get more exposure, and we can make adjustments to our flash after.

Keep in mind we will always be adjusting our aperture, shutterspeed, ISO, or flash output. But once you do this a few times, you will get the hang of it. I hope that by  using my starting exposure settings you will get Slow Sync Portraiture in a flash! Got success? Post a link and share it in the Comments below!