The Camera Settings To Keep in Mind When Capturing Crisp Movement in Studio

Here are some helpful tips on camera settings that you should use to capture crisp movement in the studio. I made a detailed video, but here is a breakdown of the settings you need to understand to keep your images sharp.

1. Choosing the Right Shutter Speed: Understanding Sync Speed

The sync speed is the fastest shutter speed that your camera can use and still sync with a flash. In most modern cameras, it is 1/200 s or 1/250 s. There are also flashes that have something called high-speed sync. High-speed sync allows a camera to go up to its maximum shutter speed, but with a significant loss of power.

Look at the following images. The one on the left was shot at f/8, 1/250 s, ISO 100. The one on the right was shot at f/8, 1/320 s, ISO 100.

The difference between the two images is a fraction of a stop of light on the shutter speed settings, but the result is about three stops under the exposure of the one on left. That is because with the image on the right, the camera went above the max sync speed of the camera and it forced the flash into high-speed sync. The flash still fired, but at significantly less power, even though the flash settings remained the same. The bottom line is that high-speed sync causes a huge drop in power in your lights.

When shooting crisp movement in the studio, there should not be any reason to force your strobe into high-speed sync. Keep your shutter speed at or just below the max sync speed for your camera.

2. Choosing the Right Aperture: Understanding Depth of Field

The next thing you need to look at is how much of the image you need in focus. When you shoot a subject and his or her eye is in focus, but the focus gets softer as you move back towards the ears, that is because you have a very shallow depth of field. Depth of field is the plane of focus that is controlled primarily by your aperture and your distance to the subject. Things that are within the depth of field will be in focus, while things in front of or behind that plane will be out of focus. The wider the aperture and the closer you are to a subject, the narrower the depth of field becomes. If the eye is in focus and the ears begin to soften, then you can raise your aperture or move farther away from your subject, and you'll see that the depth of field increases.

When you are capturing movement, you might need a wider depth of field. Imagine capturing a dancer in motion with an arm or leg outstretched or a model in a dress with flowy fabric. Always err on the side of a wider depth of field when capturing crisp movement. 

3. Eliminating the Ambient Light

When you are shooting in the studio and capturing crisp movement, the first thing you want to do is eliminate all ambient light with your camera settings. You want to make sure that the light hitting your subject is intentional light that you are controlling, not flat light from the overheads. You don't need to turn off the overheads or modeling lights. You just need to set your camera so that they are irrelevant. Start with a shutter speed of 1/250 or whatever your max sync speed is. Set your aperture to f/8 and your ISO to 100. Take a picture with those settings with the flash turned off. Your frame should be completely black. If it is not completely black, you can adjust your aperture until it is completely black, but do not change your shutter speed above your sync speed.

4. The Most Important Factor - Understanding Flash Duration

The goal is for your camera's sensor to be exposed to light for as little time as possible. That is what captures crisp movement. With camera settings that eliminate ambient light and a shutter speed at or below the max sync speed, the flash duration is the key number that will determine the crispness of your image.

Imagine you are in a completely dark room. It's so dark that it makes no difference whether your eyes are open or not; either way, you are in total darkness. Now, imagine a light comes on in the room for 1/100th of a second while your eyes are open. Your eyes could be open for 10 seconds or they could be open for a half a second. It doesn't affect the amount of time your retinas are illuminated, as long as they are open when that burst of light hits. That is how flash duration works: the amount of time your eyes are open is your shutter speed and the time that the light is turned on and off is the flash duration. The flash duration makes your shutter speed irrelevant as long as it is below the sync speed and you have eliminated all ambient light with your other settings.

Look at the two images below. The image with the paint was shot with a strobe and the shutter speed was set to the max sync speed of the camera, 1/250 s. In the image on the right, the camera was set to 1/2,000 s, and even though the shutter speed is eight times as fast, the rain is still not anywhere as crisp as the paint. The reason is that with the strobe, the motion is stopped by the flash duration instead of the shutter speed. In the paint picture, the flash duration was about 1/4,000 s. So, even with a lower shutter speed, the sensor was illuminated for a much shorter period, resulting in a crisper image.

Studio flashes put out an intense amount of light very quickly. It might seem instantaneous, but what actually happens is the flash tube ramps up from 0 to 100% brightness and then back down to 0%. That flash duration is measured in either t.5 or t.1 numbers. Here is a chart that Lee Morris put together when comparing Godox and Profoto lights:

The t.5 measures the length of time that the flash goes from 0% up to 100% and then back down to 50%. The t.1 number measures how fast the light goes from 0 then up to 100% and then down to 10% light. The t.1 number is a much more accurate reading for measuring the amount of time your camera's sensor is illuminated by the light from the flash.

The flash duration changes with the power setting of your light. If you are shooting a Godox AD600Pro at full power, the t.1 flash duration is 1/220 s. On its lowest setting, the flash duration is much quicker at 1/10,100 s. A Profoto B1 (a less powerful and three times more expensive light) is 1/377 s at full power and 1/6,010 s at its lowest setting. This is why it is important to have a powerful flash. Shooting a 600-watt-second strobe at half power and shooting a 300-watt-second strobe at full power will give you the same light output, but the closer the light is to operating at its full power, the slower the flash duration.

If you can understand these principles, it will take the guesswork out of choosing the correct camera settings for capturing crisp movement. Let me know if you have any questions in the comments.