How Digital Cameras Work

When a digital camera takes a picture, the shutter is opened, and thousands of pixels pick up light, each pixel accumulates an electrical charged based on the light that hits it, the more light, the higher the electrical charge, and the less light, the less electrical charge. After the shutter closes, the charge of each pixel is measured and then converted into a digital number and then converted to a picture by way of an analog digital converted (ADC).

The amount of detail a camera can capture is called the resolution, this is based on pixels the more pixels it has, the larger you can blow up the picture, before it turns grainy and starts to look out of focus. Some common resolutions are 256x256- this resolution may be found on very cheap cameras and is most always grainy and unsatisfactory. 640x480 is on the lower end of regular cameras, this is 307,000 total pixels. 1216x912 pixels- this is a high quality resolution, good for printing pictures, this is 1.11 mega pixels. A high resolution is 1600x1200 pixels, this is a very high resolution and images with this resolution can be printed in very large sizes with a good result this 1.92 mega pixels. Some cameras today have up to 10.2 mega pixels

Digital photography is directly related to the technology used in video recorders, both convert picture into electronic impulses. The first digital images were taken by NASA to map the surface of the moon. Probes would take pictures of the moon then convert the images to electronic signals, then send them back to earth where they would be converted back into a picture. The next major use of digital photography was for spy satellites. The first private industry sector production of digital cameras was in the 1970's when Texas Instruments produced the first film less camera which would use pictures taken onto a minidisk, which then had to be put into a video disk reader, but some say this is not actually a digital camera, but more of a video camera that takes freeze-frames. The first digital camera that could connect to a home PC was the Apple QuickTake 100 camera, which was released in February of 1994.

There are a few different ways that cameras can create color, the first, which is used mainly on more expensive, higher end cameras is done by splitting the light from the lens onto three different sensors, each with a different filter over it this makes it so that each sensor only picks up one of the primary colors. The only problem is that this tends to make cameras very bulky and more expensive. The next way to create color with a camera is to have a spinning disk with a red, a blue and a green filter on it, in front of a sensor, then the picture is taken through each of the three filters, this method is very impractical for hand held cameras and candid shots because the picture has to be taken through each filter, which may take a second. The last and most practical way to record color, is to permanently place a filter over each photosite by breaking up the sensors into a variety of red green and blue pixels, it is possible to get enough information for the computer in the camera to fill in the pixels with the true colors. There are as many green pixels as blue and red pixels combined; this is because the human eye is more sensitive to green light than red, or blue.

The great thing about digital cameras is that you can view the picture right after you take it, and then you can print the pictures with almost no hassle. Early digital cameras had a fixed memory unit inside the camera, so the camera had to be directly connected to a computer to transfer the images. Now, most cameras have removable memory cards, which can be taken and plugged into a computer to transfer the images. Some of the storage devices on digital cameras are

-Built in memory- this is only found in very inexpensive cameras

-Compact flash cards- a very popular storage device, it is very small and can hold very large amounts of data

-Memory stick- another form of flash memory used by Sony

-Floppy disk- some cameras save images directly to a floppy disk

-Writeable CD- some cameras save image son to CDs, or DVDs.

Once images have been transferred to a computer, they can then be edited, they can be cropped, rotated, resized, change the contrast, or the brightness, or you can even cut part of a picture out and put it onto another picture.