Camera Types

Most people are aware of the two major camera types, Compact and Single Lens Reflex (SLR). Compact cameras are designed for the consumer market and are very easy to use, with focus and exposure settings automatically set by the camera. SLR cameras offer the same point and shoot convenience as compacts, but have the option of manual control and the versatility of interchangeable lenses. SLRs are designed more for the serious amateur or professional photographer. Both camera types are capable of producing very clear and bright images.

Most compact and SLR cameras use 35mm film, but some are designed to use the newer Advanced Photo System (APS) film. The two film formats are not interchangeable. A camera designed for 35mm film will not accept APS film, and vice versa. When processing the exposed film, the photo developer can place either type of film onto disk or CD, enabling a home user to load the photos onto a computer. Many photo developers offer Internet access to processed photos, offering the consumer the convenience of downloading electronic versions of their photos directly to their computer.

A third camera type has entered the marketplace in the form of Digital Cameras, which don't use film at all. Images are stored digitally in the camera's internal memory, on removable memory cards, or floppy disks. Digital cameras can be connected directly to personal computers, so photographs can be easily transferred from the camera to the computer for storage, manipulation, or uploading to the Internet.

When comparing digital cameras to compact and SLR cameras, the term analog refers to any camera that uses film, and digital refers to cameras which use digital technology to store photographs.

Compact

Compact 35mm cameras are the most common and easiest to use, offering point and shoot convenience. An automatic flash is usually built in. Often, the single, non-interchangeable lens offers a modest zoom range, from medium wide view to medium close up. This zoom range greatly enhances the camera's versatility, enabling the photographer to better compose scenes without having to change position.

Viewing is done through the camera's viewfinder, which usually offers a fair approximation of the scene. Because the viewfinder is slightly offset from the lens, the view is never completely accurate. Some camera viewfinders are better than others in this regard.

The film speed rating is automatically detected by the camera, which is used as a basis for setting the exposure values for the shot. Focus and aperture settings are done automatically by the camera for optimum exposure. Most cameras produce very good results, but there are some circumstances that can fool the camera's automatic settings.

For instance, most cameras try to focus on the object that is closest to the center of the frame. If the center of the photographer's interest is outside that area, the camera may focus on the background and not the intended subject.

The main advantages of compact cameras are their compact size, relatively low cost, and the ability to produce very good photographs under most conditions, with minimal input from the user.

Single Lens Reflex (SLR)

Single lens reflex cameras have that universally recognized "camera" shape, consisting of the camera body and a detachable lens. The camera has various attachment points for accessories such as a tripod, remote shutter release and flash. Most new models contain a small built in flash, while retaining the "hot shoe" for a larger detachable flash.

The viewfinder's light path is directed from the lens via a mirror and prism, so that the photographer can see the image through the lens itself. This offers the greatest accuracy when focusing and composing a scene, because the same image is projected onto the film during exposure.

The term "single lens" refers to the fact that a single lens is used to both view and photograph your subject, while "reflex" refers to the mechanical operation of the camera during exposure. Normally, the light from the lens is immediately reflected upward, through a prism, and then out the viewfinder for the photographer to see. When the shutter is released, the mirror momentarily moves up and out of the light's path in a reflex action, so that the light can be focused onto the film at the back of the camera. During exposure, the light passes through the lens directly to the film, without being reflected by the mirror to the viewfinder. This is why the image temporarily vanishes from the viewfinder when the shutter is released.

The main advantage of the SLR is its versatility. The photographer can choose from automatic, semi-automatic, or completely manual control over shutter speed, aperture, and focus, and can thus tailor the shot for specific needs. The lens of the SLR is interchangeable, offering nearly unlimited choice of optional lenses with differing focal lengths, from wide angle to telephoto. Some lenses offer an adjustable zoom range, while others are of fixed focal length. Some lenses have a macro setting, for extreme close-up photography of objects just a few inches away. It is possible to attach filters to the lens, for interesting visual effects.

There are many optional accessories the photographer can purchase for an SLR camera, to customize the photography experience or to fill specific requirements. Some accessories include a control for off-camera flash units (for improved lighting of the subject), motor film advance that allows the shooting of several frames per second, and tripods which can provide a stable platform for longer exposures.

Disadvantages of the SLR include a relatively bulky size when compared to the smaller compact cameras, and the high cost of some full-featured models and accessories.

Digital cameras

Introduced in the late 1980's, digital cameras have improved in quality and price to the point of being worthy competitors to analog compact cameras.

Digital cameras take photographs by focusing light from the lens onto a charge-coupled device (CCD), which converts the light to electrical signals. The data is projected onto a grid of pixels, with each pixel assigned a color and brightness value. All the pixels taken together form the entire image. The image data is then stored in the camera's internal memory, on a memory card or floppy disk, if present. All digital cameras have a small preview screen to view the images stored in memory.

The camera can be connected to a personal computer for downloading the photos to the computer's hard drive for storage. One can then easily view, print, or post the photos to the Internet, if desired.

The number of pictures that can be taken depends on the memory capacity of the camera (or card/floppy), and the resolution setting for the photograph. Most digital cameras have several resolution settings. Low-resolution photos take up less memory, but may be too small to print or enlarge to the desired size without losing detail. These photos are fine if they will only be used for monitor display. Because of their small size, they are also ideal for uploading to the Internet.

High-resolution photos take up more storage space, but the extra information present in these photos produces better results when printing or enlarging. If they will only be displayed on a monitor screen, this extra detail is usually unnecessary. Additionally, the large file size of high-resolution photos can make them impractical for uploading to the Internet.

Exposure control and focus is automatic, but some digital camera models offer a degree of control over shutter speed, aperture, and focus. Lenses are usually not interchangeable, but some models have a wide zoom range. The regular zoom range (optical zoom) can be enhanced by the camera's built in software (digital zoom), for a stronger telephoto effect. Digital zoom can be effective, but when taken to extreme the image can take on a "pixelated" appearance. This is because digital zoom enlarges the pixels that make up the image, not the image itself.

Since there is no film to develop, users can avoid the expense and delay associated with film processing. The photos are digital to begin with, so there is no need to have prints or negatives scanned to load the images onto a PC. Images can be viewed immediately using the camera's preview screen, viewed on a computer monitor or printed within moments of the snapshot being taken.

At present, the disadvantages of digital cameras are cost and image quality, though each is improving rapidly. The average purchase price is currently higher than analog compact cameras, and the image definition of most digital cameras is not on par with that of 35mm film, although some high-resolution cameras come very close to matching this quality.

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Last modified: July 2008