Light is the most important aspect of photography, we can’t shoot a picture without a source of light. In fact, the word photography itself means “Writing with Light” in Greek. A wise photographer once said that “Amateurs worry about equipment, professionals worry about money but the masters always worry about light.
In high-speed photography, our main light source is flash most of the time. The reason behind it is that in high-speed photography, we use a narrow aperture to get deeper depth of field and we have to use high shutter speed so it requires lots of light which is not available naturally, that’s why we need to use and an artificial light source like flashes.
So, let’s find out why it’s absolutely necessary to use flashes.
Okay, check out the following image, I took this picture in bright sunlight with 100 ISO, F/11 aperture and 1/4000 shutter speed. As you can see that this picture is completely dark because the light was not enough to expose the picture.
To get proper exposure I had to bump up ISO to 25600 which is not advisable as it produced a lot of grains and make the picture unusable, you can see the grains on the picture itself and also see the 100% crop of the picture at the bottom right side corner.
You may be thinking what if we shoot with lower shutter speed like 1/500. Okay, let’s do some more experiments. The next photo is taken at 1/500 shutter speed with f/4 aperture and ISO was 400. Now ISO is okay but you can see that water drop is not frozen and it’s showing motion blur. Also at f/4, you’ll get very shallow depth of field and your entire subject may not be in focus properly.
Let’s take some more photos with 1/2000, 1/4000 and 1/8000 speed but even at 1/8000 you can notice a little bit motion blur and to get such speed, ISO has bumped to 6400 which produced lots of grains and don’t forget that we are still at f/4 aperture.
So now you can see that even 1/8000 seconds shutter speed is not fast enough to shoot high-speed photos and most of the camera doesn’t go beyond 1/8000. This is the reason you have to use flashes because with a good flash you can go up to 1/30000 seconds of shutter speed and absolutely freeze the moment.
Other than this when you use natural light, you don’t have much control over it. Natural light is usually flat and it doesn’t bring out depth and detail in photographs. But with flash, you have full control over the direction, intensity, color, and softness of light. Even you can use multiple flashes and illuminate the subject according to your taste. You can also use gels to create a dramatic effect which is not possible with natural light.
There is one more reason to use flashes and that’s “Shutter Lag”. Every camera has a shutter lag and because of that, there are more chances that you’ll miss the shot even though you click the shutter at the exact moment when the action is happening.
If you don’t know what shutter lag is, let me explain it to you. According to Wikipedia “In photography, shutter lag is the delay between triggering the shutter and when the photograph is actually recorded. This is a common problem in the photography of fast-moving objects or people in motion”.
So, when you press the shutter and camera click the picture, there is a delay of 30-50 milliseconds and this delay makes it harder to capture at the perfect moment. But in case of flashes, you can fire them at the exact moment to capture the picture.
So now we know the importance of flashes, in the next article we’ll talk about how to choose a good flash for high-speed photography.
About the Author
Ramakant Sharda is an author, iOS App publisher, passionate photographer and a MIOPS Ambassador based in the beautiful “Pink City” of India, known as Jaipur. His work has been published in various magazines, newspapers, and blogs. He has published three Coffee Table Books, he writes about photography and also teaches photography in his workshops. Check out his website http://ClickManic.com to see the masterpieces created by him or download his free app for iPhone and iPad “30 Days to an Ace Photographer“.