RSS FeedThe Tricky Flash Sync
What is the Flash Sync? How do I use it? And how do I achieve a high-speed sync?
These are a few questions you ponder about after getting your first ever external flash. First let’s clarify the meaning of “Sync”. Sync is actually a shortcut of synchronization, and synchronization is the way two objects function, move, execute at the same time in it’s simplest sense.
Now Flash Sync is all to do about the Flash Shutter. The Shutter is like your eyelids. It closes and opens much like your eyelids does. However for the Flash Shutter, the wider it is open and the longer it stays open, the more light is captured by the camera sensor. Basically, the camera sensor only sees light, that is why photography in it’s simplest description is a means of capturing light. If the shutter is blinking fast, which is a fast shutter, the sharper the image and the quicker your camera sensor captures the image while sacrificing the amount of light it captures as well.
Therefore, slow-shutter speeds are good for low-light conditions, making fast moving objects blurred, making running water from streams and waterfalls appear silky-smooth and taking night photographs and especially useful on time-lapse photography.
Fast-shutter speeds is good for fast targets to make them appear like you stopped time, or freeze the moment. Good for pictures of sports, racing, active kids and the like. However, you need ample amounts of light to get proper exposure at fast-shutter speeds. You can hand-hold your camera and take sharper images. For slow-shutters, a tripod is absolutely needed.
This answers your questions about high-speed sync and flash sync. It is the relation of your camera shutter with your your camera flash.
The shutter of your camera has its own rating for maximum speed which you can use the flash. Thus your camera also has a limit as to how fast the shutter curtains (eyelids) can be made to move. At higher speeds, a second shutter curtain which is rarely noticed also move to increase the speed capacity of the camera.
The secondary shutter is released before the first curtain has finished moving. This will appear like your camera sensor is shooting through moving strips.
Thus the higher the shutter speed, the thinner the strip is. This affects your flash reliability to properly expose or light up your subject. If the flash fires while the curtains are about to close, the the proper flash exposure is not taken. Thus the timing between the flash and the shutter, which is your sync speed, is essential. They must thus work in harmony.
Fast Sync, notice how the action and the crowd is captured
Slow Sync, notice that the crowd is now blurred by panning the shot.
The maximum shutter speed where the camera sensor is properly exposed when it is wide open is called the “Flash Sync” or “X-Sync” speed. It usually ranges at about 1/200 – 1/500sec. However this varies depending on the SLR/Camera.
Your external flash needs to cope with this value. That is why your reliable on-camera flash fails at higher sync speeds or your camera won’t allow you to shoot at higher sync speeds at all. Most external flash has a “High-Speed Sync” mode, allowing your camera to use any shutter speed. Notice that without your external flash attached to your camera, the camera shutter speed option is limited. Your external flash does this nifty little trick to synchronize with your camera shutter. Your naked eyes cannot see this, but to achieve high-speed sync flash, your dedicated external flash fires a series of several flashes as opposed to what your eyes can see which is a single fire of your flash. This is timed to match the period where your camera sensor is exposed. This multiple fire at high-speed sync reduces the intensity of your flash considerably, so most high-speed sync shots is done best for fill-flash at close range.
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- Selvino Wilmar Rodrigues: Another question: you said to Michael that Flash Nissin Di622 will work out of the chamber...
- Selvino Wilmar Rodrigues: You know if the Di622 will work with the Canon sx20 IS?
- Chris Administrator Gee, Please...: Sorry, only authorized technicians can do that, however If you can find the...
- Chris Administrator Gee, Please...: It should work. However, you can contact Nissin for your particular model. Also...
- Mathieu: Thanks for the link Chris… I already contacted them. Btw, if I decide on modifying it by myself, what...
- PTZ camera: Hey, wonderful blog you got here! Keep up the good job
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- Mathieu: Hi Chris, One more thing, Do you have any idea where do you think i can have my Di622 for Canon have its...
