How to Use Shutter Speeds for Creative Effects

A digital single lens reflex (D-SLR) camera (such as the Canon EOS 40D) gives its users creative options. Unlike a simple point-and-shoot camera, a D-SLR camera has creative modes that allow for manual adjustment of shutter speeds and aperture settings.

Canon calls these modes Creative Zone modes and they are represented as P, Tv, Av, M and A-DEP.

• P = Program AE Mode
• Tv = Shutter-Priority AE Mode
• Av = Aperture-Priority AE Mode
• M = Manual Exposure Mode
• A-DEP = Automatic Depth-of-Field AE Mode

In this article we will discus the Shutter-Priority AE Mode (Tv). We are primarily interested in the effect of varying shutter speeds and the special effects we can create by doing so.

WHAT IS SHUTTER SPEED?
The shutter is a device that acts like a curtain to control light reaching the sensor (or film on a 35mm film camera). The shutter speed is the length of time that the shutter allows light to expose the sensor.

Shutter speeds are stated in seconds such as 3", 2", 1", 1/30, 1/60, 1/125, 1/250, 1/500. The fractions are usually displayed simply as 30, 60, 125, 250, 500 in your Canon LCD.

Since the camera does not accurately display a fraction of a second, it differentiates between 30 seconds and 1/30 of a second by using the quotation mark ("). So 30" means 30 seconds and 30 in the LCD refers to 1/30 of a second and NOT 30 seconds.

WHY DO WE NEED TO ADJUST SHUTTER SPEEDS?
In the "auto-everything" mode, the camera sets the shutter speed and aperture for us. This is usually fine for our vacation and candid shots. However, there are times when we have to take control of these settings in order to get dramatic images that elicit a "WOW!"

We adjust shutter speeds to blur motion, freeze motion and prevent the effects of camera shake.

To illustrate the results of varying shutter speeds, take a look at these images of a portable cooling fan. Notice how the rotation of the blades is interpreted by different shutter speeds.

At a fast shutter speed (1/640 of a second) the blades appear to be at rest. Actually, the fast shutter speed froze the movement of the blades. In this case the stated shutter speed does not convey a sense of motion because the image does not show that the blades are rotating.

At 1/250 sec there is a slight indication of motion. The shutter speed is still too fast to give a true sense of motion.

In this indoor environment, shutter speeds of 1/100 sec and slower show varying degrees of motion. At 1/60 of a second the blades are clearly rotating with dramatic effects.

WHAT'S THE BEST SHUTTER SPEED TO BLUR MOTION?
There is no one shutter speed that is considered the "best" to blur motion. We can only say that slow shutter speeds usually under 1/60 sec are effective in blurring motion. The shutter speed that is best for a given scene or occasion depends on a few factors.

The speed at which the object is moving will affect the shutter speeds we use to blur motion. The lighting condition indoor or outdoor will also affect the shutter speeds (and apertures) that can be used.

One great thing about a digital camera is the fact that the images can be viewed a few seconds after taking them. Also we can shoot hundreds of photographs with a memory card, view the images, delete the ones we don't like and take more photographs.

Our digital camera allows us to experiment. If the moving or rotating object is in a controlled environment (like a studio or a house) we can take the first photograph at say 1/90 sec and reduce the shutter speed for the subsequent photos. We can try speeds of 1/75, 1/60, 1/45, 1/30 and 1/20 of a second to see the varying degrees of motion blur. Holding a camera while shooting at 1/30 or 1/20 of a second will produce camera shake so the use of a tripod is highly recommended. A Canon IS lens is an alternative if a tripod is not available.

In case we have to shoot quickly because we have no control over the moving object, then we can start at around 1/45 or 1/30 of a second. An IS lens would be perfect in this situation since the use of a tripod may not be convenient.

Photographing water in motion can be very challenging and rewarding at the same time. Raindrops, cascading waterfalls and meandering rivers are opportunities to capture the majesty of nature with our digital camera. In the absence of these natural occurrences, we can select something more common like a water sprinkler or a shower head to show the hair-like strands of water in motion.

The image to the right was taken a under a cloudy sky around 1:00 pm at Tree Tops Park (Davie Florida). In the absense of bright sunlight, I was able to use a slow shutter speed of 1/10 of a second and a low ISO 100. The camera was set on a time delay and secured to a Bogen tripod to prevent camera shake and blurred image. My Tamron SF AF 17-50m lens was set at 40mm. In bright sunlight a very slow shutter speed necessary to blur the flow of water, is difficult to get. Hence, this setup is best done early or late when the sun is low in the sky or on an overcast day.

Ps. The photographs of the rotating fan were shot with my Canon EOS 40D camera and Canon EF 24-70mm f/2.8L USM Zoom Lens mounted on a Bogen tripod. The lens was set near 45mm. The Shutter-Priority AE Mode was used. I manually set the shutter speeds and the camera automatically set the aperture settings, which varied from f/2.8 to f/7.1. ISO 400 was used for all images.