Types of Photographic Camera - Lecture 4


CAMERA

The camera is a device for recording or capturing images usually consisting of a lightproof box with a lens at one end and light-sensitive film at the other. A digital camera records or capture images in digital form using an image sensor such as charged coupled device (CCD) or CMOS (complementary metal-oxide-semiconductor)and stores these images on to a storage medium. These stored images can be easily transferred to a computer immediately.

Digital and film cameras share an optical system, typically using a lens with a variable diaphragm to focus light onto an image pickup device. The diaphragm and shutter admit the correct amount of light to the imager, just as with film but the image pickup device is electronic rather than chemical. However, unlike film cameras, digital cameras can display images on a screen immediately after being recorded, and store and delete images from memory. Many digital cameras can also record videos with sound. Some digital cameras can crop and stitch pictures and perform other elementary image editing.
Currently, many brands of consumer and professional-grade cameras are available in the market on the basis of budget, utility, quality and features. Selection of camera depends on the purpose of use and the budget. DSLR cameras produce high-quality images while they are costly.


POINT AND SHOOT CAMERA

A point-and-shoot camera, also called a compact camera, is a still camera designed primarily for simple operation. Point and shoot cameras mean just that point the camera at subject or object and trip the shutter. A point and shoot camera might also be the best camera for beginners who just want to see if photography is something they are really interested in. The camera does all the work for you. Point and shoot cameras are small, light weight and can be carried in a pocket. These cameras tend to be cheaper then SLR cameras. Many of these cameras offer a built in macro mode allowing extreme close-up pictures. Most use focus free lenses or autofocus for focusing, automatic systems for setting the exposure options, and have flash units built in.
Point-and-shoots are by far the best selling type of separate camera, as distinct from camera phones. They are popular with people who do not consider themselves photographers but want easy-to-use cameras for snapshots of vacations, parties, reunions and other events. Point-and-shoot camera sales declined after about 2010 as smartphones overtook them in such uses. All point and shoot cameras come with fixed lenses.
Generally the quality of the images on compact cameras is not as good as that from SLR cameras, but they are capable of taking professional quality images.

BRIDGE COMPACT CAMERAS

Bridge camera as name implies it fills the gap between basic Point and Shoot cameras and Digital SLR Cameras. Bridge camera is also known as advanced compact camera because it provides more controls over camera settings than a basic compact camera. Bridge camera covers features available in a basic compact camera as well as some standard features of Digital SLR cameras. The primary Digital SLR type feature found in most Bridge Cameras will be the manual and semi-automatic exposure modes in addition to the automatic mode. It is useful for those users who don't want to pay the higher price for Digital SLR camera but still want to have creative control over the camera settings.
Some Bridge cameras having huge zoom range are called Super Zoom Cameras. Bridge cameras give the photographer more control over the lens aperture settings and shutter speeds. However, the lens on a bridge camera is fixed and cannot be changed.

SLR CAMERA

The most popular type of general-purpose camera for enthusiasts and professionals is the single lens reflex (SLR).This type of camera has a moveable mirror behind the lens which reflects an image through a five-sided prism (pentaprism) or pair of mirrors, onto a glass screen (the viewfinder). This means the photographer sees exactly the same image that will be exposed on the recording medium (film or digital CCD).With Twin lens reflex and rangefinder cameras the viewed image could be different from the final image. When the shutter button is pressed on a mechanical SLR the mirror flips out of the light path, allowing light to pass through to the light receptor, allowing the image to be captured. Prior to the development of SLR, all cameras with viewfinders had two optical light paths: one path through the lens to the film, and another path positioned above (TLR or twin-lens reflex) or to the side (rangefinder). Because the viewfinder and the film lens cannot share the same optical path, the viewing lens is aimed to intersect with the film lens at a fixed point somewhere in front of the camera. This is not problematic for pictures taken at a middle or longer distance, but parallax causes framing errors in close-up shots. Moreover, focusing the lens of a fast reflex camera when it is opened to wider apertures (such as in low light or while using low-speed film) is not easy.
Most SLR cameras permit upright and laterally correct viewing through use of a roof pentaprism situated in the optical path between the reflex mirror and viewfinder. Light, which comes both horizontally and vertically inverted after passing through the lens, is reflected upwards by the reflex mirror, into the pentaprism where it is reflected several times to correct the inversions caused by the lens, and align the image with the viewfinder. When the shutter is released, the mirror moves out of the light path, and the light shines directly onto the film (or in the case of a DSLR, the CCD or CMOS imaging sensor). The Canon Pellix film camera was an exception to the moving mirror system, wherein the mirror was a fixed beam splitting pellicle.
Focus can be adjusted manually by the photographer or automatically by an autofocus system. The viewfinder can include a matte focusing screen located just above the mirror system to diffuse the light. This permits accurate viewing, composing and focusing, especially useful with interchangeable lenses.

Up until the 1990s, SLR was the most advanced photographic preview system available. Nearly all inexpensive compact digital cameras now include an LCD preview screen allowing the photographer to see what the CCD is capturing. However, SLR is still popular in high-end and professional cameras because they are system cameras with interchangeable parts, allowing customization. They also have far less shutter lag, allowing photographs to be timed more precisely.
Some of the basic characteristics of an SLR include:

• Removable lenses that can be switched out to include a variety of situations
• More control over focus and zoom, as well as better granularity in these controls
• Better flexibility and capability with exposure which allows for more creativity with how the picture is taken
• Little or no lag time when taking pictures
• Generally better quality pictures since the lenses are made of higher precision glass
• Usually no video or features normally found on consumer-level cameras
• Typically very expensive, especially lenses and accessories.

DSLR CAMERA

Digital SLR cameras are the most versatile and advanced type cameras available in the market. DSLR stands for “Digital Single Lens Reflex”. In simple language, DSLR is a digital camera that uses mirrors to direct light from the lens to the viewfinder. When you look through the viewfinder on the back of the camera, whatever you see is exactly what you are going to get in the photograph. The picture that you are taking passes through the lens in the form of light into a reflex mirror. This mirror reflects the light coming through the lens upwards at 90 degree angle. It is then reflected by the pentaprism to the photographer's eye. During exposure (when the photograph is taken), the mirror swings upward, and a shutter opens, allowing the lens to project light through the aperture onto the sensor.
By setting DSLR camera in the automatic mode we can simply take pictures. However, it also has the option of taking pictures in the manual mode, Aperture Priority, Shutter Priority, or program modes. DSLR Cameras are popular with camera enthusiasts is that there are more choices as to which camera exposure settings can be used as well as the option to change the camera lens.
The first thing about a Digital Single Lens Reflex camera is that it is larger than any compact consumer camera. In Digital SLR cameras lenses can be changed to fit different situations. The lenses for Digital SLR cameras will generally be of a better quality than those found on compact cameras which will result in better image quality. Another big difference between Digital SLR cameras and compact cameras is the
image sensor size. Digital SLR cameras have larger image sensors which will generally produce better quality images.
DSLR or the Digital version of SLR is basically an SLR that has been converted from saving the image in film to saving an image in a memory card. It still shares a lot of the advanced features of the SLR along with a few more improvements that makes it a lot more superior.
Despite being a few folds more expensive compared to their counterparts, the SLR and the DSLR were an indispensable tool in professional photography. The DSLR is just the next evolutionary step from the SLR.
The digital single-lens reflex camera have largely replaced film SLR's design in convenience, sales and popularity at the start of 21st century.

SLT CAMERA

Single-Lens Translucent (SLT) is a Sony proprietary designation for Sony Alpha cameras which employ a pellicle mirror, electronic viewfinder, and phase-detection autofocus system. They employ the same Minolta A-mount as Sony Alpha DSLR cameras.
Sony SLT cameras have a semi-transparent fixed mirror which diverts a portion of incoming light to a phase-detection autofocus sensor, while the remaining light strikes a digital image sensor. The image sensor feeds the electronic viewfinder, and also records still images and video on command. The utility of the SLT design is to allow full-time phase-detection autofocus during electronic viewfinder, live view, and video recording operation.

MIRRORLESS INTERCHANGEABLE-LENS CAMERAS


In late 2008, a new type of camera emerged called mirror less interchangeable-lens camera (MILC), which uses various sensors and offers lens interchangeability. These types of digital cameras are very similar to Digital SLR cameras. Mirror less Interchangeable Lens cameras allow the photographer to use the camera in full manual, automatic, or semi-automatic modes the same way Digital SLR cameras can be operated. These are simpler and more compact than DSLRs due to not having a lens reflex system. Their camera body size is closer to the size of compact cameras. The reason the body size is so much smaller is because they do not have optical viewfinders like the Digital SLR cameras. They are equipped with an LCD screen and/or Electronic Viewfinder for previewing the scene that is about to be photographed. The mirrors in a Digital SLR camera take up a lot of space in the body of the camera, so the elimination of the mirrors allows for a smaller body to be used for the mirror-less camera.

Mirrorless Cameras are geared toward photographers who want the better image quality that is associated with Digital SLR cameras without the bulky size of a Digital SLR. They are also built to appeal to those who like the smaller size of a compact digital camera, but also want the option of being able to change the camera lens to adapt to
different picture taking situations. Mirrorless Camera removes the jerk from the bounce/recoil of the mirror, makes camera steady.
Olympus and Panasonic released many Micro Four Thirds cameras with interchangeable lenses which are fully compatible each other without any adapter, while the others have proprietary mounts. In 2014, Kodak released its first Micro Four Third system camera.
As of March 2014, MILC cameras are available which appeal to both amateurs and professionals.
Digital Single Lens Translucent (DSLT) camera: A DSLT uses a fixed translucent mirror instead of a moving reflex mirror as in DSLR. A translucent mirror or trans missive mirror or semi-transparent mirror is a mirror which reflects the light to two things at the same time. It reflects it along the path to a pentaprism/pentamirror which then goes to an optical view finder (OVF) as is done with a reflex mirror in DSLR cameras. The translucent mirror also sends light along a second path to the sensor. The total amount of light is not changed, just some of the light travels one path and some of it travels the other.



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