Shutter Speed

Shutter Speed

The first variable is shutter speed!

This is going to sound a little crazy but your shutter speed actually does absolutely nothing when it comes to your flash exposure. The flash fires so quickly that your shutter speed is simply not fast enough to affect the flash!

Your shutter speed setting will only affect AVAILABLE LIGHT (can also be referred to as Ambient Light). Available light is any continuous light source that is not the flash. It can be the sunlight, moonlight, a candle or a lamp. Anything that does not flash is available light. In the example above you can see the first shot was taken at 1/50th of a second shutter speed. If you roll your mouse over the image you will see the second shot which was shot at 1/125th of a second shutter speed. The shutter speed was the only thing that was changed and notice the difference in the background. The background is available light, the shutter speed controls it. By making my shutter speed faster, the available light is cut down, but the flash exposure on my subject is the same!

There is something you should remember about available light. Available light is always constant on everything, including the subject you are illuminating with flash. So if your shutter speed is slow enough to allow available light in, there will also be available light that is hitting your subject. That's why sometimes it might appear that your flash exposure is also controlled by your shutter, but it's not. It's simply the available light that is constantly hitting your subject!

I want everyone to start understanding exactly how light works, so I'm trying to be as detailed as possible! Any questions, just leave it in the comments!

Light is measured in stops, and shutter speed works in stops as well. Anytime you double or halve the speed of your shutter you are adjusting your exposure by one full stop. You can also adjust your exposure in 1/3 and 1/2 stops. But we will get into that a little later. Just note that shutter speed works in stops. This will be important when we put it all together because all other variables work in stops as well and they are all related!

You can control the amount of available light in your photo by adjusting the speed of your shutter. Just like in Natural light photography, the faster the shutter speed the less time the sensor has to capture light. The slower the shutter speed the more time your sensor has to capture light. For example, if you take a shot and your background is underexposed, you need to slow down your shutter speed to allow more available light into your camera. Or if you take a shot and your background is overexposed, you need to increase your shutter speed to allow less light in to your camera.

In flash photography unlike natural light your shutter speed will have a speed limit which is called your Max Sync Speed. This is the limitation that you have when you are shooting your flash in Manual Mode. If you go above your Max Sync Speed (in most camera's it's 1/250th of a second) you will see a black bar at the bottom of your image! This happens because your your shutter begins to close before the flash has had a chance to fire, the flash and the camera are not in sync. That's why they call it Max Sync Speed, this is the fastest speed your camera and flash will sync at. If you are shooting in CLS or TTL, you can overcome this by using High Speed Flash Sync (I don't personally use it, but I'll have articles of other photographers who do), but for now we will talk only about using the flash in Manual Mode which is the best and easiest!

Another thing to keep in mind when it comes to shutter speed is that it will also control the motion blur of your image. Just like in natural light photography if you have a very low shutter speed, your images may come out blurry. When I'm shooting and I have to adjust my shutter speed, I am always careful not to lower it to speeds that may cause motion blur, whether it's because I'm shooting in low light or I'm shooting something that is moving.

The important thing to understand is that your shutter speed will only control available light! Keep this in mind and in the PUTTING IT ALL TOGETHER article, I'll...well put it all together!