High Speed Sync and How It Works
On this video, photographer Jay P. Morgan from the website the Slanted Lens takes a look at an important topic – High Speed Sync – what it is, how to use it, advantages and disadvantages and more.
To understand what is high speed sync and how it works, we need to first understand how shutters work. Most camera shutters are two curtains that open and close. Morgan explains that at speeds slower than 1/125th, or 1/60th depending on your camera, the first curtain open completely before the second curtain begins to close. At faster the first curtain of the shutter opens and before it is completely open the second curtain starts to follow it and close. This means that there is no time that the sensor is open to light all at once. A small slit travels across the sensor exposing the frame it as it goes. If your strobe goes off during this time, it show a black bar at the bottom of the frame, basically the part of the image that was not exposed to the strobe flash.
This problem is solved by using high speed sync by firing the strobe fast in pluses as the first curtain opens and continues to pulse until after the second curtain closes. It happens so fast that the sensor perceives the flash as continuous light. This does have drawbacks – it reduces the power and reduce the battery life – but this is a pretty good trade-off.
Next Morgan shows how to use High Speed Sync on the Baja B4 (each strobe will work a bit different).
You can check out more on Morgan’s blog post on this video.
We have already looked at some of the basics of conventional flash sync on several videos in the past including “Understanding Flash Sync Speeds” with Karl Tylor and “Flash Sync Speed and Flash Duration” with Mark Wallace.