A digital camera captures and stores images electronically by using image sensors instead of photographic films. They are multifunctional and high-end digital cameras have multimedia capabilities by recording sound and video.

Numerous styles and types of digital cameras
Digital cameras can be broadly classified into main three groups according to its functions, namely, still digital cameras, video digital cameras, and professional modular digital camera systems. However, the distinguishing features are becoming blurred with advancement in digital camera technology, and most still digital cameras have audio-video function, whereas most video digital cameras can also take still digital photos. Many still digital cameras have a 'movie' mode, where images are acquired on a continuous basis at a frame rate that is sufficient for video display.

Still digital cameras

• Standard digital cameras or snapshots - Most digital cameras available in the digital camera store fall in this category. They are also known as snapshots, are easy to operate, allow easy focusing, have an extended depth of field making objects at different depths come in focus at the same time, are widely used for landscape photography and even for casual use, and they save the digital photos in JPEG or TIFF format. They are low to moderately priced.

• Prosumer digital cameras - The term 'prosumer' is a combination of 'professional' and 'consumer'. These digital cameras physically look and behave like professional SLR cameras but are aimed at the common consumer, hence the name 'prosumer'. These digital cameras have extended, large zoom lens with barrel distortion and pincushioning features. Some zoom models have image stabilization. They generally have fixed lens, and some models also feature removable lens where additional lens can be attached along with filters, remote controls, and external flashes. They can take still digital photos, record audio and video, have a LCD display or an EVF (Electronic View Finder) to enable scene composition. They are lighter in weight and more compact than a DSLR (digital SLR), are capable of high image quality and can save digital photo in JPEG, TIFF or RAW format. They are moderate to high priced.

• DSLR (Digital Single Lens Reflex) cameras - These digital cameras are designed for the use of professional photographers. They have high burst rates are very well adapted to sports and action photography. They retain the features of the conventional film SLR cameras, the image composition is done through the optical viewfinder which uses a mirror reflected image, which is more precise than an electronic viewfinder. They have the ability to change lenses, and some cameras allow the same lenses as used in 35mm SLRs. The image sensors are larger and thus have greater sensitivity to dim light and the digital photos have less noise overall. They are fast and start almost immediately with autofocus and other features. Most of the DSLRs can save digital photo in JPEG, TIFF, or RAW format, either individually or simultaneously. They are bulkier and more expensive. Due to the reflex viewfinder movies cannot be recorded, and the screen is used only to review still pictures. Latest digital camera technology can allow the DSLR to use the LCD for a live preview, and soon DSLRs will be able to record and view movies. They are highly priced.

Video digital cameras

• Camcorders - Amateurs use these digital cameras. They feature a microphone to record sound and have a small LCD to see the video while recording or playback. Low-end digital tapeless systems store in flash memory and use MPEG codec whereas high-end digital camcorders store uncompressed or DV-coded data on the hard disk. Modern camcorders use HDTV MPEG codec which allows broadcast quality HD on a standard MiniDV cassette.

• Webcams - These are digital cameras that are attached to computers. They can be used for video conferencing or can also be used for chatting. Webcams can capture full-motion video and high-end versions have microphone and zoom facility.

• Professional video digital cameras - These cameras are used for television and movie production. They usually have numerous image sensors, usually one per color, to enhance resolution and provide a wide color gamut. They generally have to externally connect the microphone and do not have an inbuilt VCR.

Professional modular digital camera systems
As acceptance of the digital cameras grew, many photographers who had 35mm film cameras wanted to convert their film cameras into digital cameras, instead of buying new digital cameras. The cost of reworking was high and so it was not possible. However, to allow a bit of space for the electronic parts and an LCD screen for previewing, the back of the 35mm film camera had to removed and replaced with a digital unit which was custom built. These modular digital units fitted at the back of a 35mm film camera came to be known as 'digital backs'. Instead of a film, a device was inserted at the back that had an image sensor of 1.3 mega-pixels resolution and a capacity of 24 shots. Larger backs with 10 mega-pixels also came out and medium to large format cameras, which used film stock greater than 35mm, willingly accepting the change. These cameras are modular, with separate film backs, winders, lenses, and handgrips, to suit various needs. These backs have main three methods of capturing the images, namely, single shot, multi-shot, and scan. Advanced cameras like a digital rotating line camera uses a fourth method of a rotational scan of a linear sensor. The subject matter that is to be photographed and the type of digital camera determine which method has to be adopted.