When I am out shooting, I am always trying to think of how I can get the most out of my equipment. I am thinking about how I can expand my ability to create using my camera, lenses, and filters. And, what about my flash, what I can I do with that? Flashes today are a lot different than when I started in photography. Back then you had a manual mode and an auto mode and that was about it.
Most modern flashes today have a multitude of functions. Balanced fill flash, front curtain, and rear curtain sync. High-Speed Sync also is known as FP (focal plane) mode. Some flashes can be set to fire multiple bursts creating several flash images on a single frame. Many flashes available today are set up to be used off-camera. Back in the good old days if you wanted to get your flash off of the camera you could use an off-camera cord. That was OK for close work but the wireless flashes setup of today permit unlimited flash positioning.
One of the modes I use quite a bit is the High-Speed Sync or FP mode.
First a little bit about how it works.
High-Speed Sync is also known more accurately as Focal Plane flash. Here it is in a nutshell. flashes and cameras have a maximum shutter speed that the flash can be synced to. On most of the older cameras that was 1/125th of a second. Cameras today can sync at 1/250th. With these cameras, if you set a higher shutter speed one speed faster than the sync speed, you will get a black band usually at the bottom of the image. If you increase the shutter speed another stop faster the black band will double in width. So if your camera has a sync speed of a 1/250th and you set your shutter speed to 1/500th you will see that black band. Increase the speed to 1/1000th and the band doubles in width. Go ahead, increase the speed to a 1/2000th and see what happens?
This occurs because the flash and camera cannot, in the normal mode, sync to the higher speed, and the black band is caused because the shutter is not open all of the way when the flash fires.
In the normal flash setting, the flash waits to fire until the instant that shutter curtains are open all of the way. The flash only fires for that instant.
In High-Speed Sync. Wait. Let’s call it the focal plane mode or FP mode because that helps explain what is happening. In FP mode when you press the shutter button on the camera the flash starts firing. The flash continues to fire all of the time that the shutter is opening and closing. So the functional difference between the standard and FP mode is that in the standard mode, the flash fires only for the instant that the shutter is all of the way open. In the FP mode, the flash is firing and continues firing during the entire operation of the opening and closing of the shutter, thus there is no black band.
When we use the FP mode we have to be aware that the flash is working very hard to put out that continuous flash and so flash distance is decreased. Also, the batteries are being drained at a faster rate and the flash may heat up if fired continuously. When I use this mode to shoot water drops, I have my camera set in high-speed continuous shooting mode and my Nikon SB-900 would get to the point of overheating and shut down to protect the flash. So how hot was hot? So hot, that I would open the battery door and drop the batteries out on to a plate. I did not want to hold those batteries in my hand. Not for long anyway.
Ok, so that is how it works now on to what does it do for me?
High-Speed Sync is useful for almost all types of photography. It can be used for shooting portraits. It can be used when shooting sports as long as you are close enough to the action and have a powerful enough flash. Small flashes can be convenient to carry around but if you are planning on buying a flash to do this kind of shooting my advice is to go big or go home! To get any good distance when in FP mode you need a flash with a lot of punch! That said, I have been using my little Promaster 100SL. Coming in just south of $150.00, it has been doing a pretty darn good job at garden distances.
If you are going to use a flash in FP mode for portraits or sports I would recommend a more powerful flash unit.
Lately, I have been using the 100SL flash in FP to shoot hummingbirds, bees, and plants and flowers on my deck. Did someone say quarantined?
I use the FP mode to get high shutter speeds when I am shooting the little birds to slow down the wings and to slow down the fast-moving birds in general. I get a stop action effect that I do not quite get at the slower shutter speeds. Using the high shutter speeds also causes dramatic flash fall off creating dark, sometimes black backgrounds that make the bird stand out. When I shoot flowers with the fast shutter speeds I get the same result. Very dark backgrounds that make the colors of the flowers pop! Sometimes people who shoot a lot of plants and flowers will carry a piece of black velvet to place behind the subject to get that black background. I have done that, but it is kind of a pain because it is another thing to carry and it also picks up lint and little pieces of debris that are almost always white (Murphy’s Law) and they show up in the photo so I have abandoned the velvet practice and now just use my flash to get the darkened background effect.
Here are a few pictures. See how the dark background makes that flower pop when compared to the version without the flash.