In most of the cases you would probably hit the delete button straight away, when you check your pictures and see a blurry image. The main objective of photography is usually to have a clear and crisp subject in focus. However, when used right, a bit of a blur can be quite interesting and give your image a sense of motion.
So how to achieve this effect? When mixing strobe light and ambient light with a slow shutter speed, the strobe will “freeze” part of the subject while the ambient light coming in at slow shutter will create a motion trail before the subject. One of the most common and suitable subjects to photograph with this technique is the juvenile Harlequin Sweetlips due to its nature of moving around constantly.
For some subjects though you will have to create the motion blur yourself. You can either pan, go side to side or back and forth as well as rotate the camera when you press the shutter. It’s crucial to get the timing right with all these movements – the subject or camera will have to move whilst the shutter is open.
Here are two different examples: I kept my camera still at 1/6 sec whilst the Flamboyant Cuttlefish was moving. With the juvenile Ambon Scorpionfish I’ve moved the camera from one side to another at 1/5 sec to create the motion trail.
Give it a try on your next dive and see if you’re enjoying this technique since it can make an usual suspects stand out a lot more!