Understanding Shutter Speed

What Is A Shutter Speed?

In film cameras, the shutter is the device that opens and closes to control the time that light is allowed to passed through the aperture to the film. Digital cameras ( excluding DSLRs ) however use an electronic switch that tells the camera for how long to turn the image sensor on. Some DLSRs use a combination of physical and electronic shutters.

Shutter speeds are measured in seconds, with typical mid-range cameras featuring shutter speeds from 1/2000 of a second to 15 seconds. More advance digital cameras can hold the shutters open indefinitely ( example: "bulb" mode )

The main reasons for having variable shutter speeds are, first, to achieve the desired exposure for different aperture settings, and also, to affect the way moving subjects appear in resulting photos.

Effects Of Shutter Speeds
When the shutter speed is left open/on for a prolonged period. Two things happen.
1.) The brightness of the scene become increasingly amplified, and
2.) The most minute of movements during the exposure shows up in the resulting photograph.

Slow Shutter Speeds
It's not a strict rule, but some photographers refer speeds below 1/30 as "slow". 
Slow shutter speeds are used for situations where the photographer wants to capture and convey the effect of motion on a still photograph or for night photography where the sensor requires more time to record the scene due to lack of light. Slow shutter speeds are also used when small apertures are used. On another note, they also allow more natural-looking ambient light to illuminate a subject, sparing the need for flash. It's important to use a stable platform when using slow shutter speeds though, in order to prevent blur.

Fast Shutter Speeds
Faster shutter speeds are ideal for freezing motion. Situations that require high shutter speeds include sports, wildlife, or child photography because the subjects are constantly on the move. Extremely high shutter speeds are sometimes combined with a rapid sequential shooting of photos in a professional camera's burst mode, resulting in a sequence of shots of the subject in motion. Bear in mind that as shutter speeds increase, more light is needed to create proper exposure for the picture. You can achieve this by simply adjusting the camera's aperture of ISO sensitivity settings.

Flash Usage

The camera's flash is an often misunderstood accessory!

Novices mistakenly tend to use the flash as a cure-all for all sorts of inadequate lighting conditions. Proper employment of flash, however, requires certain techniques for various situations. There are various types of flash modes that every photographer must understand in order to be able to use them appropriately. The regular type of flash is also known as front curtain sync, which simple fires the flash when the shutter first reaches its peak opening, thus freezing motion at the beginning of exposure. On the other hand, rear curtain sync fires at the end of the peak shutter opening, allowing photographers to make creative use of motion trail effects.
If you want to capture subjects standing against an attractive night scene involving glittering lights in the background, slow sync flash is the mode use. Using this technique effectively, however, requires that the subjects won't move throughout the long exposure. :)

I hope you enjoy reading the 4th part of digital photography basics.
Later then. ^_^

Enjoy capturing light! 


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