Stroboscopic Flash Photography

I seldom use flash. Very very seldom even though I have had an external flash, Canon 580 EX, for few years already. I love natural light and any other available / ambient light when shooting. Almost all of my photos at Masakecil were taken without flash. But every now and then, I use flash for some creative photography, like the ones here. They were shot using stroboscopic flash technique.

I first used this stroboscopic flash technique in 2006 when I shot my cousin’s pre-wedding photos. See below. Do you notice the softer flash light for the photo below? That’s because I used the LightSphere flash diffuser. I didn’t use it just now.

I wanted to do it again tonight, so I asked my daughter if she would like to help her daddy. She ended up having too much fun and didn’t want to stop. I had to stop it because she has a field trip to a library tomorrow morning with her school and she is not a morning person … yet. She’d better be next year when she starts her primary school.   🙂

When a flash is set to be in Stroboscopic mode:

• the flash will emit pulsating flashes of light
• the camera will be able to capture (read: freeze) moving subject multiple times in one shot

Cool right? No photoshop needed.

Most of the theory on stroboscopic flash will recommend you shooting against black background in order to avoid the background to be over-exposed. But, for me,  I like to mix it with ambient lighting in the background, unless the shot is for some specific subjects that really require black background. I will try to find some time to do this later.

Some important factors to note when setting your flash in stroboscopic mode:

• the firing frequency or cycle per second (Hz). 1Hz means something happen once in a second. 5Hz means something happen 5 times in a second.
• number of flashes per cycle.
• the speed of the moving subject (usually the faster the movement, the more flashes you would need in order to capture / freeze more movements).
• you need to set your camera to Manual mode. The minimum shutter speed to use is (number of flashes per cycle) divided by (the firing frequency or Hz).
• the power of the flash.

So, for 10 flashes at 5Hz, you need to set the shutter speed to at least 2 seconds. This will give the flash unit enough time to fire the number of flashes you choose.

What about the power of the flash? When your  flash is set to function in stroboscopic mode, the flash unit is splitting its power to each burst of light. So 1/16 will mean each burst will have 1/16 of the full power of the flash. Less power will mean less light. Just go ahead to experiment how bright you want the subject to be.

Have fun.