History of Digital Camera

By : Dontanisha WilliamsP2

• Digital cameras are incorporated into many devices ranging from PDAs and mobile phones ( called camera phones) to vehicles

• Unlike film cameras, digital cameras can display images on a screen immediately after being recorded, and store and delete images from memory.

Advantages of professional digital cameras

• Immediate image review and deletion is possible; lighting and composition can be assessed immediately, which ultimately conserves storage space.

• High volume of images to medium ratio; allowing for extensive photography sessions without changing film roll.

• To most users a single memory card is sufficient for the lifetime of cameras whereas film rolls are re-incurring cost of film cameras.

Performance metrics

• Lens quality: resolution, distortion, dispersion • Capture medium: CMOS, CCD, negative film,

reversal film, etc.• Capture format: pixel count, digital file type

(RAW, TIFF, JPEG), film format (135 film, 120 film, 5x4, 10x8).

• Processing: digital and / or chemical processing of 'negative' and 'print'.

Pixel Counts

• The number of pixels n for a given maximum resolution (w horizontal pixels by h vertical pixels) is the product n= w * h.

• This yields e.g. 1.92 megapixels (1,920,000 pixels) for an image of 1600* 1200.

Methods of image capture

• Single-shot capture systems use either one sensor chip with a Bayer filter mosaic.

• Multi-shot exposes the sensor to the image in a sequence of three or more opening of the lens aperture.

• The third is a scanning.• Their linear or tri-linear sensors

utilize only a single line of photo sensors, or three lines for the three colors.

• The Bayer arrangement of color filters on the pixels array of an image sensor.

• The Bayer filter pattern is a repeating 2*2 mosaic pattern of light filters, with green ones at opposite corners and red and blue in the other two positions.

• Sometimes a 4-clolr filter pattern is used, often involving two different hues of green

• Green is a human visual system, which determines brightness mostly from green.

Sensor size and angle of view

• Cameras with digital image sensors that are smaller than the typical 35mm film size have a smaller field or angle of view when used with a lens of the same focal length.

• The amount of information captured is dependent on sensor density.

Compact digital cameras

• Compact cameras are intended to be portable and particularly suitable for casual “ snapshot”.

• Compact cameras are usually designed to be easy to use, sacrificing advanced features and picture quality for compactness and simplicity; images can usually only be stored using lossy compression (JPEG).

• Starting in 2011, some compact digital cameras can take 3D still photos.

• These 3D compact stereo cameras can capture 3D panoramic photos for play back on a 3D TV.

• In 2013, Sony released two add- on camera models without display, to be used with a smartphone or tablet, controlled by a mobile application via WiFi.