'Photo' is a Latin word that means 'light' and 'graphy' means 'recording'. When you take a photograph, you record that particular moment of light and capture it on a media interface. In traditional cameras this media is present in the form of a photographic film.
In digital cameras, light is allowed to fall on sensors (charge couple devices) that are sensitive to light. The amount of light that falls on the light sensor is called exposure. A digital camera shutter allows the light to fall on its light sensors only when you take a photograph and that too, for a set period of time which is called the shutter speed.
These are the three factors that help calculate the duration of the exposure.
- Aperture setting of the digital camera.
- Light meter of the camera.
- Amount of light available.
Placed between the lens and the light sensors is the shutter which controls the amount of light falling on the light sensors. Digital cameras convert this light to digital signals that are stored and are used to display the images or photographs on the display screen.
Each and every camera has a shutter, that acts as an exposure-controller. In digital cameras, a shutter is either a mechanical or an electronically-controlled barrier.
The shutter speed needed to photograph a moving object and a static object are different, and a photographer needs to adjust it accordingly. Your digital camera may have a 'B' setting, through which you can leave the camera's shutter open for as long as you want. You may want to do this in case you are photographing an object in pitch darkness.
Whilst using the 'B' setting, you must take the precaution of setting the adjustable image noise reduction feature of your camera, to full. Some old model digital cameras, experience problems when the 'B' setting is used for very long exposure.
When you change the speed, you need to adjust the aperture hole accordingly. If you change the shutter speed of 15 seconds to 30 seconds, then it means that you are doubling the amount of light falling on the light sensors of the digital camera.
If you are using the 'S' feature of your camera, then it allows you to set the shutter speed in such a way that you can automatically adjust the aperture hole to reduce the amount of light passing through the lens to compensate for the correct exposure. For daylight digital photography, maintain a speed between 1/125th to 1/1000th of a second.
You may have seen a program on the television, which shows a recording of a bullet fired at an apple. We can see the bullet hitting the apple, piercing it, coming out on the other side, and then the impact making the apple explode. Well, a bullet travels at the speed of more than 1,200 feet per second, then how can one record such a fast-moving object?
The camera used to record the sequence has a very high shutter speed and can record 10,000 pictures a second. Of course it is a digital camera. If you are interested in wild photography and want to photograph a hummingbird, then is the daylight shutter setting enough? No!
The hummingbird flaps its wings 400 times a second. You need a very fast shutter speed setting to photograph this bird in flight, else the photograph will appear blurred. Which digital camera and lens will you now use to photograph the hummingbird?
Think about it and then go about your task, of course, you will have to refer to a few digital camera buying guides so that you understand which would be best suited for this task and your other needs. Even then, it's always better to go through a few catalogs and weigh out your options before settling for one.