Digital Photography

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Digital Photography
Quick Photography Tip
Some of the best pictures are taken when the people in them had no idea they were being photographed

Definition:

* Uses a digital camera to electronically capture and produce images using a CCD. Scanners, software, computers and printers are used together with the camera to produce the finished image.

* Taking pictures with a digital camera and storing and printing them on digital devices. The "digital film," which is comprised of flash memory modules, floppy disks or CD-Rs, can be transferred to a local computer for printing, or can be uploaded to a Web site for viewing and printing.

* The art and science of producing and manipulating digital photographs -- photographs that are represented as bit maps.

* A type of photography in which images can be viewed on a computer screen.

* A method of photography in which an image is digitally encoded and stored for later reproduction.

Digital photography, as opposed to film photography, uses an electronic sensor to record the image as binary data. This facilitates storage and editing of the images on personal computers. Digital cameras now outsell film cameras and include features not found in film cameras such as the ability to shoot video and record audio. Some other devices, such as mobile phones, now include digital photography features.

Sensors

There are two main types of sensors:
* charge-coupled device (CCD) - charge is shifted to a central charge-to-voltage converter
* CMOS sensors

There are also two main types of sensor mechanisms possible:
* Area array
* Linear array (in professional "scanning" camera backs)


An area array sensor reads the entire image plane at once, whereas a linear array sensor works more like a flatbed scanner. Since this technology predates area arrays, it was available earlier, in professionally-priced studio cameras. With the advent of area array sensors, consumer digital cameras became available for considerably lower prices. (The Ritz Dakota Digital is an extreme example.)

Multifunctionality and connectivity

Digital cameras can usually take pictures and additionally sound and video. Some can be used like webcams, some can use the PictBridge standard to connect to a printer without using a computer, and some can display pictures directly on a television set. Similarly, many camcorders can take still photographs, and store them on videotape or on flash memory cards.

Most digital cameras can connect directly to a computer in order to store pictures or to be used as a webcam. Digital cameras generally include a USB or FireWire port, and a memory card slot. There are also cameras available that can send pictures directly to a PictBridge compatible printer.

Performance metrics

The quality of a digital image is the sum of various factors, many of which are similar to film cameras. Pixel count (typically listed in megapixels, millions of pixels) is only one of the major factors, though it is the most heavily marketed. Pixel count metrics were created by the marketing organizations of digital camera manufacturers because consumers can use it to easily compare camera capabilities. It is not, however, the major factor in evaluating a digital camera. The processing system inside the camera that turns the raw data into a color-balanced and pleasing photograph is the most critical, which is why some 4+ megapixel cameras perform better than higher-end cameras.

* Lens quality: resolution, distortion, dispersion (see Lens (optics))
* Capture medium: CMOS, CCD, Negative film, Reversal Film etc.
* Capture format: pixel count, digital file type (RAW, TIFF, JPEG), film format (135 film, 120 film, 5x4, 10x8).
* Processing: digital and / or chemical processing of 'negative' and 'print'.

Pixel counts The number of pixels n for a given maximum resolution (w horizontal pixels by h vertical pixels) can be found using the formula: n = wh. This yields e. g. 1.92 mega pixels (= 1,920,000 pixels) for an image of 1600 x 1200. The majority of digital cameras have a 4:3 aspect ratio, i.e. w/h = 4/3.

Advantages of digital: professional cameras * Immediate image review and removal, lighting and composition can be assessed without wasting storage space. * The ability to shoot in RAW format (images that contain tagged data directly from the sensor). However, as of this writing, there are a number of proprietary RAW formats, some of which require specific software to manipulate. * Faster workflow: Management (colour and file), manipulation and printing tools are more versatile than conventional film processes. However, batch processing of RAW files can be time consuming, even on a fast computer.


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