+ Shutter Speeds

+ What is the Shutter Speed?

+ Video Camera Shutter The Term Shutter comes from photography and shutter speeds are used in photography in a different way to video but have the same effect. In photography it refers to the mechanical door between the lens and the film. When you take a photo the mechanical door (shutter) is open for a set time (speed) when the door is open the film is exposed to the incoming light. The speed at which the shutter opens and closes can altered, the slower the speed the longer the shutter is open and the more light is exposed to the film and visa versa.

+ How it is measured Measuring shutter speed is very easy to do. It is the amount of time that the shutter on your camera is open, recorded in a fraction of a second. For example, if you have a shutter speed of 1000, then the shutter will open for 1/1000th of a second. Generally, shutter speeds are categorized into fast, slow and long shutter speeds. Fast Shutter Speeds A shutter speed is considered fast when it is above 500, or open for 1/500th of a second. The purpose of a shutter speed this fast is to capture movement without it coming out blurry.

+ Slow Shutter Speeds Shutter speeds that are considered slow are ones that are slower than 1/60th of a second. It is at these speeds that an average person will not be able to hold the camera still for long enough to get a decent picture. In photography a slow shutter speeds should not be used without some sort of stabilization for your camera, or you will get something called camera shake, but very interesting effects can be made with a slow shutter

+ Video Camera Shutter Speeds Video camera shutter speeds work differently than photography but have the same result The difference is technical, instead of a mechanical door/shutter in video cameras, the shutter speed is adjusted electronically varying the amount of time the CCD is allowed to build a charge

+ CCD Charge-coupled device A charge-coupled device (CCD) is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. The CCD is a major piece of technology in digital imaging. In a CCD image sensor, pixels are represented by p-doped MOS capacitors. These capacitors are biased above the threshold for inversion when image acquisition begins, allowing the conversion of incoming photons into electron charges at the semiconductor-oxide interface; the CCD is then used to read out these charges.digital imagingimage sensorpixelsp-doped MOSphotons Wikipedia

+ Video Camera Shutter Speeds The Shutter “opens” and “closes” once for each frame of video that is, 25 times per second for PAL and 30 times per second for NTSC. Thus, if a camera has its shutter set to 1/60, each frame will be exposed for 1/60 second. If the speed is increased to 1/120, each frame will be exposed for 1/120 of a second The speed does that effect the frame rate

+ High and Low Shutter Speed The main effect of higher shutter speeds is that individual frames appear sharper, due to the minimisation of motion blur. Motion blur occurs when the subject moves within the frame while the shutter is open. The less time the shutter is open (i.e. the faster the shutter speed), the less movement will take place. One side-effect of higher shutter speeds is that movement appears more jerky. This is because motion blur tends to smooth consecutive frames together.

+ Video Shutter Speeds 1/120 second1/500 second No Shutter The three shots below were each taken as the car travelled past a stationary camera at 100 km/hr. With the shutter off, motion blur is most pronounced. As the shutter speed is increased, the image becomes sharper. Higher shutter speeds are common in sports coverage. Watch any fast-action sport to see the "flickering" shutter effect. Notice how the slow-motion replays look, especially when they freeze the last frame.