HIGH SPEED PHOTOGRAPHY FOR BEGINNERS
The use of high-speed cameras for still image photography and cinema has become widely popular. Although modern advances have made this technology more readily accessible, the key techniques have been around since approximately the mid-1800s.
What is high-speed photography?
In still photography, high speed refers to photographs created with a one millisecond or shorter exposure time. High-speed video includes actions that are captured at 250 FPS or faster. FPS is a term to describe frame rates per second. The frame rate is how often frames are displayed. If an event is seized at 250 FPS and played back at 25 FPS, it will appear to have slowed down by a factor of 10.
Early photographers understood that mechanical shutters had limited abilities when it came down to speed. In the mid-1800s a high-speed shutter was introduced to photograph cannonballs in motion. The exposure was 1/50 second, by current standards that is rather slow, but at its time was groundbreaking.
How have shutters evolved over the years?
Generally, to create a bright light pulse, bare electric sparks were often used to halt rapid motion. They were about a fraction of a millisecond long. Today’s modern shutter on a DSLR or digital single-lens reflex camera can manage exposures of 0.25 millisecond. However, the electronic flash units that accompany these models are small and may offer exposures that are only around 0.025 milliseconds. That amount to ten times less than what the camera offers.
When attempting to capture a fast event, a good technique breaks down into three key steps: method, moment, and duration. This just means that the quality of your results is determined by the way you look, the time you look, and the duration. All three steps, along with having a quality high speed camera such as a unit from IDT are equally important. The method is mainly how the lighting and equipment are put in place. The moment and duration are all about the right timing, which is the trickiest components to control.
Can a DSLR capture high speed events efficiently?
Low key fast events can be recorded with a DSLR, a small flash unit, and a cheap timing device. Specialized gear isn’t always necessary. The use of an electronic flash instead of shutter speed is what the high-speed still photography method is all about. To avoid blur, transient actions need extremely brief exposure times. This means lots of light during that very short span.
A DSLR with a fast shutter may still lack sufficient existing light for the best exposure. Also, since a shutter scans across the sensor at high speeds, the whole image isn’t precisely created simultaneously. This may lead to a distorted moving object in the picture.
Is it best to use a flash?
On the contrary, a flash will expose the whole image at once. However, it is hard to pre-determine how the lighting will appear, but that ability will develop with experience. A flash is also useful for getting the perfect moment. The reality is the brief delay between hitting the shutter button and opening it makes it hard to get the exact image you are trying to achieve.
The open shutter technique is much easier for grabbing the perfect moment in time. Operating in a dark room the shutter is opened on a long exposure. If there is no light, the film won’t expose. The flash activates at just the right time in the event. Quality high-speed photography is determined by how quickly the film is exposed to light. The shorter the burst of light the better.
The last parameter is duration. Whether you perfectly synchronize your camera and event precisely, anytime exposure is too long, a blurred image will result. Here, a handheld flash unit can save the day by reducing the output of power, you will shorten the flash duration and produce the desired 1/50,000 second exposure times.
What is special about high speed video photography?
The three-step approach of method, moment, and duration also apply to shooting high speed video. In contrast, to still photography, minimum flicker needs to be continually maintained while all sources of light remain on. The need for costly cameras and studio lighting puts this type of photography out of reach for many photographers.
However, high speed video photography is very well used in many scientific applications such as automotive and aerospace research, human sports performance and in manufacturing industries. The artistic value shines in the business of cinema and television. High-speed photography crosses the line that often separates science and art.