Understanding Your Digital Camera-2

Film cameras were around for many, many years. Around 1860, a handful of early photographic pioneers started taking pictures with a box called the camera obscura. They coated glass or metal with light-sensitive emulsion and inserted them into the camera box through a slot in the side. Some people back then thought that having your picture taken would steal your soul... I guess all things that are new to us have a tendency to make us skeptical.

To best understand your new (or slightly older) digital camera, you should know how it differs from a film camera.

As we learned in lesson 1, the camera is nothing more than a light-tight box. Inside this box is the light sensitive media. But in the days of film cameras, we had to be much more careful not to expose the film before or after we used it to take pictures.

Let's look at the film camera and some it's parts and then compare them to some of the digital camera parts of today.

First, you always need a lens. It is the only way to get the image onto the film or image sensor. The diameter of the lens is fairly critical if proper exposure is to be achieved. If the lens is too small around, it doesn't let much light in. If it is a zoom lens, the light gets less as the zoom is applied. Finally, there are aperture settings which also influence brightness.

To understand aperture, think of the iris of your eye. When you are in bright sunlight, your brain tells your iris to contract or cut down the amount of light. If you are in lower light, the iris opens up more to let light in and you can see in the dimmer light. Finally, later in the day toward dusk, your iris opens even further to let the most light into the eye as possible so that you can make sense of where you are. Once your iris open to its fullest, you are then going to need a flash light to see any better. You have just understood how the lens and flash work on a camera.

Behind the lens is the shutter. The shutter opens like a door rather quickly and for a predetermined amount of time to let a volume of light into the area where the film plane is, these days called the light sensor.

This mechanism is controlled by the "brains" of the camera's exposure called the metering system. Whether automatic, programmed, semi-automatic or just manually set, the metering system plays a role in telling the shutter how long of a time to open. This is usually counted in portions of a second. Common shutter speeds are 1/250, 1/125, 1/60, 1/30, 1/15, etc. Can you see how they get longer and longer as you progress. This means that the longer the shutter is open, even for a portion of a second, the light is striking the film or image sensor. If you consider this concept along with the apertures above, you now have most of the controls used to make a picture.

In today's digital cameras, most everything is automated. You don't need to change film and you don't even need to know how the camera works as long as you can turn it on and press the exposure button. If that is enough for you to consider, you may want to stop reading here and just go take simple pictures.

But if you are at all intrigued by this device, read on and see what other information will help you take really good images!