SYNCHRONISATION
Managing sychronisation is normally straightforward but requires an understanding of what is going on with the camera and the flash gun which have to work together.

In the simplest terms the flash duration is usually about 1/1000th of a second.

The camera’s shutter is normally adjusted for studio work to be around 1/100 sec.

Therefore when the camera shutter is opened there is a lot of time to fire the flash tube before the shutter closes.

If the studio is dark only the flash light will be seen by the camera.

In normal practice the photographer considers the flash head to be equivalent to an aperture and the shutter is adjusted for adequate opening time considering only the synchronisation.

For example to take a one light portrait with the flash set at one side of the subject and with the subject sitting in relative darkness, the photographer might set the flash head to f8.

If the shutter is set for 1/100th or 1/60th or 1/30th sec matters not.

This is a critical part of understanding what is going on.

With inexpensive heads, setting f8 can be a problem. Having placed the light where you want it in relation to the subject, if it can only be half or fully bright, it is unlikely to be f8. Clearly you may be able to adjust the aperture, but as soon as you introduce a second light, the problem becomes quite difficult to manage.

Professional heads can be set exactly how you want them within quite wide limits.