High Speed Flash Sync

by William Lulow

Last week I decided to make some swimming/splash shots of my granddaughter, Dylan who is a very good swimmer. I had an idea about what I wanted the shot to look like, but wasn’t sure exactly how to set it up. Shots like this take quite a bit of planning but often a lot more practice to get right. I also don’t make these kinds of shot often, but I wanted to do some experimenting.

I set up two strobe lights set for HSS (High Speed Sync) on either side of the pool and began doing some test shots. This is what part of the set up looked like:

That’s Dylan’s dad loading up a cup of water and here is one of the shots:

Here, the water droplets are captured, but they don’t seem to make sense with what is happening in the photo. So we decided to do some more experimenting with Dylan just jumping in the water and capturing the splash. This shot was made with a 135mm f/2 lens on my Canon 90D. Exposure was 1/640th of a second at f/3.5, ISO 100.

This is me capturing the action shots of Dylan jumping and splashing the water:

Notice I have turned the flash around to aim it toward the action. The flash was set to HSS and just about full power. I was shooting at 1/640th of a second at f/7.1 with my Canon 85mm f/1.8 lens. ISO was 400. This is one of the shots:

Here, the splash looked normal and I had to remind Dylan to look at the camera as she jumped into the water. Again, this kind of shot takes a lot of practice. You might have to go over and over it in order to catch the water and the expression just right. This image was made with my 85mm f/1.8 lens on my Canon 90D, ISO 400, f/4 at 1/1000th of a second.

These are fun shots to do. Here is another:

The trick to doing these types of images is that the High Speed Sync needs to be enabled on each flash unit you intend to use. This shot was made with the 85mm f/1.8 lens, 1/1000th of a second at f/3.5, ISO 100.

You can’t use normal flash settings because the highest shutter speed that the normal setting would work is around 1/400th of a second. That would be good for shooting an event where the shutter speed was around 1/125th of a second, which is fast enough to stop most action with people talking or walking in a room. It wouldn’t be able to capture splashing water however.

If the shutter is not synced with the flash, you would most likely get a picture of the shutter opening and closing, thereby blocking some detail. So you need to have both the flash and the shutter in sync to capture the “stop-action” drops of water.