Shutter speed, it’s different than what you think.

It’s important to know when your taking a picture what elements are used in the camera to make the proper exposure. “Why, my camera automatically sets things. I don’t even have to think about it” you may say, but if you want more control over the control of light and consider what the camera “believes” is correct then you’ll want to know this.

There are three things that make an exposure. ISO (the camera’s sensitivity to light), aperture (this control’s how much main or active light is used), and shutter speed (how much ambient or background light is used). The balance of these three create a correct exposure. By manipulating any of these three you can greatly affect the mood or purpose of the image.

Today we’ll focus on shutter speed alone. In the following images the ISO and aperture will remain the same at ISO100 and f/ 8.0. The flash is camera left about one foot away set at 1/32 power with a diffusor set in front. The room has an overhead dining room light on and there is a window with closed blinds behind the camera with daylight coming through. The only thing that’s going to change is the shutter speed with it initially being set at 1/100th of a second.

 

shutter speed 001

You’ll notice that all ambient light is eliminated and only the flash is lighting the scene. If the flash power was set little closer to the cup there would be only a black background and the cup would be brighter.

shutter speed 002

In this shot the shutter speed is slowed to 1/60. Notice how the background is starting to show and the window light is lighting and little on the right side of the cup.

shutter speed 003

At 1/40 the scene is still primarily lit by the flash but the chair back on the right is beginning to show like a shadow.

shutter speed 004

Now at 1/25 of a second the ambient light is beginning to light the scene a little. You can see the back wall and the shadow top left is filling in. Also you’ll notice the right side of the cup is being filled in by more of the sunlight from the window.

shutter speed 005

At 1/15 more of the light is used for the background. It’s a bit moody but could be used as a very early morning concept.

shutter speed 006

1/10th is really using the ambient light better than the previous settings. You’ll need to forgive the color balance. I set it for the flash lighting and not the window and overhead tungsten light.

shutter speed 007

1/6th of a second is, in my opinion, showing nicely exposed. The flash is illuminating the left side of the cup as fill and there is nice specular highlights on top.the rest of the cup is lit by the window and the overall background is lit by the overhead light.

shutter speed 008

The last couple of shots will show how dragging the shutter even longer to 1/4 and 1/2 respectively brings in more of the ambient light and mostly eliminates the flash.

shutter speed 009

 

Next post we’ll see how by changing the aperture we can control how much active light is used.

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About Mark Birks
Professional photographer specializing in fine art photography and portraiture.

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