Digital Cameras Information
Digital cameras encode digital images and store them for later reproduction. They make up the majority of cameras sold today and are integrated into smartphones, tablets, and other devices.
Digital cameras are equipped with a similar optical system as film-based cameras, using a lens with a variable diaphragm that focuses light on a device designed to capture images. They rely on an electronic image sensor to convert incoming light into discrete digital signals and store it in an electronic format.
In a digital camera, captured images are instantly viewable as they are stored on a solid-state memory unless deleted from the device. Several cameras support basic image editing functions such as cropping, stitching, and other image enhancement features. Video and sound recording are common additional functions.
Digital imaging utilizes two main types of sensors: a charge-coupled device (CCD) or the complementary metal-oxide semiconductor (CMOS). In CCD sensors, all pixels share a single amplifier, whereas CMOS provides each pixel with an amplifier of its own. However, quality of the digital image is determined by the camera's image processing capability, rather than the type of sensor used.
The image sensor determines camera resolution. Brighter images captured by the sensor represent a greater number of pixels, which is used to calculate a camera's "pixel count" by multiplying the number of rows and columns. For instance, a 2,000 by 2,000-pixel sensor would contain 4,000,000 pixels, or 4 megapixels.
Digital cameras provide several benefits over conventional film cameras, including:
- Storage: Digital cameras hold hundreds or thousands of pictures compared to 24 or 36 in film
- LCD screen: The screen is used to view, edit, or delete photos and videos immediately after being captured
- Size: Digital cameras encode photos in an electronic format and store image data in memory cards. Because they do not need additional space to accommodate a roll of film, they are very compact and portable.
There is a vast array of digital cameras covering a range of prices and capabilities, including the following:
Digital single lens reflex (DSLR) cameras: These cameras are the most advanced consumer digital cameras available in the market. They allow the user to take photos in full auto-mode with the camera automatically adjusting all settings for the user. They differ from compact digital cameras in size and control over exposure settings. Common settings include custom programming, manual mode, shutter priority, and aperture priority. DSLR cameras with detachable lenses allow the user to change the lens and accommodate a wide-angle shot or close-up photography. DSLRs use various zoom lenses covering a broad range of focal lengths. The image sensor size is larger in DSLRs compared to standard compact digital cameras, which results in a higher picture quality.
Compact digital cameras: Also called point-and-shoot cameras, they have a large range of different prices and features. Most current models fit in a pocket or a small carrier and have a minimum resolution of 12 megapixels, providing a high image quality with an option to enlarge them further. Compact digital cameras feature an automatic mode for straightforward point-and-shoot along with distinctive modes that create a quality image in unique scenarios. Unlike the more powerful DSLR cameras, a basic compact camera does not offer any adjustments to settings such as shutter speed or lens aperture.
Bridge compact digital cameras / super zoom cameras: Also called advanced compact cameras, they bring enhanced performance over basic compact cameras. Additional exposure settings are the main difference. The majority of these cameras have a full manual mode giving the user complete control over exposure needs. Bridge cameras feature lenses with enhanced zoom ranges at more than five times. Cameras with unconventionally long zoom ranges are referred to as "super zoom" cameras. Bridge cameras feature non-detachable lenses that cannot be changed. They are smaller than DSLR cameras and larger than most compact models.
Mirrorless interchangeable lens cameras: As with DSLR cameras, MILCs feature lens interchangeability with a plethora of manual controls. The main differentiating factor is the physical size. MILCs are smaller as they do not have an optical viewfinder, a component commonly found in DSLR cameras.
Industrial digital cameras: Also known as machine vision cameras, these devices are made up of two main components: an image sensor and a digital interface. The digital interface takes the pixels produced by the image sensor and converts them into digital gray levels. Once converted, the results are processed to form a picture that transfers to a computer. Industrial cameras are widely used in the scientific, medical, and security fields as well as in machine vision applications.
Unlike consumer cameras, industrial cameras do not use image processing to beautify the images captured. The main objective is precision, as they convert light intensity into a digital signal. Also, for machine vision purposes, image compression is avoided. Given the vast range of applications, industrial cameras come with lens mounts, allowing end users to determine the type of lens most suitable for their purpose.
Private and commercial users use digital cameras in numerous applications. These include:
- Recreational and leisure time photography
- Commercial photography (weddings, graduations, posed photographs, sports, reporting etc.)
Lighting scenarios and the degree of manual overrides are two important considerations. Compact or point-and-shoot cameras adequately serve many consumer applications by utilizing automatic settings for everyday use. Bridge or MILC models offer more settings or a longer zoom range. MILC or DSLR cameras are better suited for professional photography and offer superb image quality and accommodate different shooting environments. Cameras intended for industrial use require research to match the camera's capabilities with the array of individual needs of the application.
ISO DIS 18383 - Specification guideline for digital cameras
ISO 15781 - Digital still cameras - Measuring shooting time lag, shutter release time lag, shooting rate, and start-up time