How to use the front curtain synchronization and Hou Lian synchronization of photographic flash?

When shooting a moving object with a low-speed shutter in the evening, at night or indoors, if the front curtain is used for synchronization, after the flash flashes, because the subject is still moving, it will leave a virtual shadow of the subject moving in front of the exposure position; However, if the Hou Lian is used for synchronous shooting, although the virtual shadow of the moving subject will still be photographed, the flash will flash before the Hou Lian is turned off, so the subject can be clearly photographed. For example, at a wedding, Hou Lian was used to photograph the newlyweds and people holding candles marching in sync. The newlyweds were photographed clearly on the picture, but the light of candles was left behind the newlyweds, and the picture was full of romantic feelings.

There is no difference between the two methods of shooting still life, mainly because the effect is very different when shooting moving objects (such as cars with headlights on). Another difference between the two is that if the subject is a frontal portrait, under the synchronization of the frontal curtain, because the flash flashes first, people often make some reaction actions after being flashed by the flash, such as closing their eyes and blinking, which will also be recorded in the later shutter time; Hou Lian synchronization, because the flash is at the moment when the shutter is about to close, even if there are actions such as blinking, the shutter has been closed and will not be photographed.

The front curtain flashes synchronously, that is, flashes first. If there are moving scenes and people in the picture, the image just taken will be blocked, which is mainly used to take pictures with clear subjects when the light is dim.

Hou Lian synchronization is used for objects that want to express motion. The process is basically like this: open the Hou Lian synchronously, open the shutter to pull out a series of moving images, and finally turn on the flash to freeze the main body. Finally, the frame is very clear, with a series of shadows in front, showing the movement with special effects.