High Speed Photography Tutorial: Have you ever wandered how photographers were able to capture a water splash, bursting balloon, a bullet hitting a fruit?
The goal of the high speed photography is capturing objects in motion. You can photograph events that follow a predictable sequence. In all cases you want to be able to detect a trigger, wait for an event and take a picture.
For example, in order to capture a falling drop hitting the surface of water, first you need to detect the time when the drop starts falling. Next, you create a delay between the trigger and the event. Finally you take the picture.
There are two methods for performing high speed photography with the timer. The first method uses a shutter of a camera. The second method uses an electronic flash.
The main advantage of the shutter method is that it can be used outdoors. The subject and the background can be fully illuminated. Since the shutter is used to freeze the motion of the subject, it offers a limited speed. Maximum speed of a shutter could range from 1/4000sec to 1/8000sec, in some cases it may not be fast enough (fast moving objects will become blurred).
Moreover, in cameras that have a focal plane shutter, a small slit moves across the photographic plane at much slower speeds (1/250), thus exposing different parts of the photographic plane at slightly different times.
Finally, there is a delay between the shutter release and the actual exposure. It could be as much 100ms or more (depending on camera). In addition there could be a small variation in timing, each time the camera takes a picture. Therefore this method should not be used when high timing accuracy is required.
The second method of high speed photography is the flash method. The picture is taken by opening the shutter of the camera, activating the flash and closing the shutter. The picture needs to be taken in a dark room. Because the room is dark, the long exposure time will not have any effect on the final output. The flash light duration now becomes the actual exposure time.
The main advantage of the flash method is the exposure speed and better timing consistency. Electronic flashes are capable of light strobes with durations of 1/10,000 or faster (lower the power setting of the flash, the shorter the flash duration).
The lag between the trigger and the flash strobe is insignificant. The disadvantage of this method is that the picture needs to be taken in a dark room to avoid the over exposure. Also since the flash is used to make the exposure, it may be more difficult to provide a uniform lighting or to illuminate the background.
You will require three basic components for high speed photography:
3. Photographic timer with sensors.