Sunday, August 2, 2009

What is Digital Photography?

Before we begin discussing how to use capture and compose images, it is very useful to understand the camera and photography medium itself. Digital Photography is a type of photography that uses digital technology to make images of objects and subjects.

In general though, digital photography is what it sounds like: digital. Instead of shooting on 35mm film, or 8mm film, the camera records the picture using a series of 1's and 0's. This is effectively digital data. The image taken with the camera is stored on a disc or hard drive as a digital file. Instead of the scientific process of shooting film and letting sun expose a film negative, digital cameras use a computer chip that basically acts in the film's place . As the light comes through the lens, that computer chip translates the image into a digital file, or a series of 1's and 0's.

This is taken by a special type of camera called a digital camera, one that can capture still photographs or videos by recording images via an electronic image sensor. In short this means that this type of photography does not make use of photographic film, but instead digital and computer methods, which enables much user flexibility in the number of photos taken, the editing process, storing displaying, printing, transmitting and archival. While in the film photography field we might have to be wary of the number of photos be capture, in digital photography, the number of photos captured is only limited by the size of the Memory Card. While with film cameras you have to get it developed in a dark room, with digital cameras all that needs to be done is to plug the camera into the computer, to be able to view or edit the image. You can even view the image on the LCD screen on the camera itself.

There are three main types of cameras that can obtain photos in the digital form, through Compact Digital Cameras, Bridge Cameras or Digital Single Lens Reflex (DSLR) Cameras.
Compact Digital Cameras:

(at left is a Canon PowerShot SD9OI 10MP Digital Compact Camera)

These types of cameras are designed to small and portable, usually able to fit snugly into our pant pockets. These are regularly used for casual and “snapshot” use, and through the rise of social networking websites such as Myspace and Facebook, more and more people have made purchases of this type of camera in order to take self portraits or pictures of friends and events. Due to such usage, they have often also been cited as Point-and-Shoot Cameras.
While the small designs of Compact’s are in order to be of easy use, advance features and picture quality are usually sacrificed in order to have a compact and simple camera design. Usually images can only be stored as JPEG files, which are not a lossless compression type, which means the photos will not necessarily be 100% quality. Most compact cameras also come with an in-built flash which is of low power, just capable of lighting up nearby subjects and objects. Framing of photos are usually always limited to the live preview function where you see the image as it is seen through the lens. The zoom capability is also comparatively less than Bridge and DSLR cameras. However, this also means that they have a great depth of field, which allows objects within a large range of distances to be in clear focus.

Bridge Cameras:
(at left is a Panasonic Lumix DMC-FZ50 bridge digital camera)

Bridge Cameras are basically higher end cameras that are made to physically resemble DSLR’s in size, lens capabilities, and some external and internal advanced features, but are made to share the framing of the photo using live preview and small sensor sizes. At the usual cost of distortions, Bridge Cameras can provide a very wide zoom range. This distortion of course varies between lens qualities. Due to the similar appearance to DLSR’s Bridge cameras have been known to be wrongly sold as DSLR cameras, however any person with knowledge of the camera design would know that these cameras differ to DSLR because they do not contain the mirror and reflex systems of DSLRs, and also have static lenses.
Although Bridge Cameras are slower to operate than true DSLR cameras, they are still capable of very good image quality, and are also more compact and lighter than DSLR’s, meaning they are more easy to carry around and are very good for travellers who do not want to carry much luggage, or those who want good quality shots without having to pay the extra money for a SLR camera. This is helped by the fact that many of the high end Bridge Camera models are comparable in terms of resolutions to low and mid range DSLR cameras. In addition, instead of just JPEG format, these types of cameras can also usually encode in RAW format, providing a lossless format.

Digital Single Lens Reflex Cameras (DSLR’s):

(To the left is a Sony A300 Digital SLR, my current camera)

These are cameras that use a mechanical mirror system and pentaprism to direct light from the lens to an optical viewfinder on the back of the camera, allowing the photographer to directly see what they are capturing through the viewfinder unlink other forms of cameras.

I will summarise the basic operation of the DSLR now, however I may make a new post in the future on the full workings of the DLSR if time persists. For viewing purposes, the mirror in the camera body reflects the light coming through the lens that is attached to the camera, upwards at a perpendicular angle (90 degrees). It is then totally internally reflected twice by a five sided prism called a pentaprism. This changes the direction of the light in order for it to travel to the photographer’s eye. During the actual act of exposure (when the photographer hits the button usually found at the top of the camera in order to capture an image), the mirror assembly physically swings upwards. The aperture then narrows and the shutter opens to allow the lens to project light onto the image sensor (much like the workings of the eye, where the light travels to the retina to be processed by photoreceptors on the retina). A second shutter then covers the sensor, which ends the exposure, lowering the mirrors and resetting the shutters. All of this functionality occurs automatically within a few milliseconds, and a camera can usually do this 3-10 times a second.

DSLR cameras are much preferred by professional still photographers due to the accurate preview framing of the image which is pretty much exact to the moment of exposure. DSLRs also allow users to replace and use a variety of types of lenses for different occasions and uses. Professionals also prefer DSLR photography over other variants due to their large sensors, many being the size of traditional film camera formats. For those who want to get into the professional photography field, or those who want to make some fabulous shots, we recommend you buy and use a DSLR camera.

While the first few tutorials on this site will be tailored for DSLR cameras, owners of any type of digital cameras can use these tips to enhance their photography, as many of the tips here can be used by all camera owners. More tips and guides to other forms of digital photography will be uploaded in the future as well, after the basics are set out.

Anyways, until then, go out and browse for the best digital camera for you, and happy snapping!


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