How High Speed Photography Works ?
As a commonly used term, photography generally refers to the process of capturing an image, stopping it for future viewing, evidence etc. This is quite easy with group photos, stationary objects, landscapes etc. New camera technology allows professional and amateurs to capture images of relatively slow-moving people and objects. For example, cameras with very quick shutter speeds can produce quality sports photos and wildlife photos in some cases.
But there are events that happen so quickly it is almost impossible to capture a still photo or even catch the motion in standard video. In the same sense, some objects and animals move too quickly for traditional photography and video cameras. Even the fastest, most-efficient camera from the local retail store won’t be able to stop the motion of a hummingbird’s wings, for example. What do we do in situations of this type?
First of all, stopping the movement of a speeding bullet or the motion of a bird’s wings can be done. Photographers have captured still images of horses running and in the photo all four feet are off the ground. We have all seen sharp photos of this type, even though the image would not be visible to the human eye. How do they do that?
In many cases, capturing high-speed action of this sort means returning to the use of manual settings on single-lens-reflex cameras. The photographer has to have the cameras opening set properly (the aperture) to get the right amount of light onto the film that will record the image. The photographer also has to open and close the shutter for exactly the right amount of time so that the film is exposed properly.
Understanding high-speed photography may be a bit easier if we think of its opposite – extended exposure that is used at night, for example. We want the film to be exposed for as long as possible to let in plenty of light. In contrast, capturing a horse running or stopping the bullet for a single image requires the exposure time to be very, very short. This is aided by flash times that are also very short. A controlled amount of light reaches the film for an extremely short period.
Photographers may photograph a high-speed object in complete darkness so that the tiny moment of light from the flash is all that reaches the film. For that instant, the moving object is exposed. The shutter can remain open because the film is not exposed in complete darkness. The flash time for this is measured in tiny fractions of a second, much smaller than the times used in normal photography.
Category: Technology