Advanced Video Editing


Canon XF300

Adjusting the Shutter Speed


The shutter speed measures the amount of time that the camera's shutter is open. Many people visualise camera shutters as rotating fan blades or even a garage door that opens and closes over a specified time. When closed, the light is blocked from falling onto the camera's sensor. In camcorders and DSLRs, the shutter is electronic and, because it's not mechanical, can open and close very fast. 

We use shutter speed to change the amount of light that hits the camera's sensor. The longer a shutter is open, the more light can pass through the lens. Shutter speeds are conveyed as fractions of a second. In most DSLR's the slowest shutter speed is 30 seconds, which is great when you're taking pictures of stars. However, anything with motion will appear blurred with slower shutter speeds. If you want to capture, or even freeze the motion, such as a footballer kicking a ball, then you need to use shutter speeds that last a fraction of a second.

Shutter speed can be illustrated by this image from the B&H Photo/Video store. 



In this image, taken with a DSLR, at extremely fast shutter speeds (1/2000th of a second) you can "freeze" the rotors of a helicopter in mid-flight.... 


....or suspend water droplets from a scene of turbulent splashing. 

The one thing to keep in mind is that slower shutter speeds will blur motion. In camcorders, the motion blur is most perceptible in images that are shot less than 1/60th of a second. Therefore, the baseline length for shutter speeds in camcorders should be 1/60th of a second. Sure, the image will get brighter, but at a cost. 

However, at faster shutter speeds, less light is entering the lens and the image will appear darker. Therefore, you need ample light when using fast shutter speeds, which is why it's necessary to adjust your shutter speed first before you adjust your aperture for optimal exposure.  

The Canon XF300 offers 6 modes for adjusting the shutter speed. The shutter switch is located on the side of the camera just behind the lens. Depending on the mode, the selection you make will be displayed in orange in the viewfinder over the shutter speed. 

If the shutter switch is set to OFF, then the speed will be set to 1/60th of a second for a 60i frame rate; to 1/30th of a second for a 30p fps and 1/24 for 24p fps.



Setting the Shutter 

  • To change the shutter speed mode, slide the switch over to SEL
  • Repeat to cycle through the various modes until the desired one is selected.
The shutter speed mode changes in the following order:

Auto > Speed > Angle > Clear Scan > Slow Shutter

Auto Mode - in this mode, an A will appear next to the shutter speed in the viewfinder display. This means that as the brightness in the image changes, the camcorder will automatically change the shutter speed.

Speed Mode - the shutter speed can be changed manually using the SELECT wheel next to the MENU button.

Angle - this is another expression of shutter speed, but described as angles. Angles are essentially the same thing as shutter speeds, but using a different standard. The faster the shutter speed, the narrower the angle. 

Clear Scan - with this, you can set the frequency to match the scanning rate of CRT screens to avoid displaying black bands that appear to flicker across the screen. 

Slow Shutter - slower shutter speeds can be used to brighten the picture, but the motion blur is far more pronounced. However, you might be able to use it to artistic effect. 


 

The Shutter value is highlighted in the LCD Panel