2. Pixel
• A picture element
• (pix=picture and el-element)
• In color image systems, a color is typically
represented by three or four component
intensities such as red, green, and blue, or
cyan, magenta, yellow, and black.
3. File size
• Image file size is
positively
correlated to the
number of pixels
in an image and
the color depth,
or bits per pixel
4. Types of Files
• JPEG (Joint Photographic Experts Group) is a compression method. Nearly
every digital camera can save images in the JPEG/JFIF format, which
supports 8-bit grayscale images and 24-bit color images (8 bits each for red,
green, and blue).
• The TIFF (Tagged Image File Format) format is a flexible format that
normally saves 8 bits or 16 bits per color (red, green, blue) for 24-bit and
48-bit totals, respectively, usually using either the TIFF or TIF filename
extension.
• GIF (Graphics Interchange Format) is limited to an 8-bit palette, or 256
colors.
• The BMP file format (Windows bitmap) handles graphics files within the
Microsoft Windows OS. Typically, BMP files are uncompressed, hence they
are large; the advantage is their simplicity and wide acceptance in Windows
programs.
• The PNG (Portable Network Graphics) file format was created as the free,
open-source successor to GIF. The PNG file format supports 8 bit paletted
images (with optional transparency for all palette colors) and 24 bit
truecolor (16 million colors) or 48 bit truecolor with and without alpha
channel - while GIF supports only 256 colors and a single transparent color.
5. Exposure
• The quantity of light
allowed to act on a
photographic
material; a product of
the intensity
(controlled by the lens
opening) and the
duration (controlled
by the shutter speed
or enlarging time) of
light striking the film
or paper.
[Brightness/Darkness
of the final photo]
6. Shutter Speed
• shutter speed or exposure
time is the effective length
of time a camera's shutter
is open. The total exposure
is proportional to this
exposure time, or duration
of light reaching the film or
image sensor.
7. Aperture
• an aperture is a
hole or an opening
through which light
travels. More
specifically, the
aperture of an
optical system is
the opening that
determines the
cone angle of a
bundle of rays that
come to a focus in
the image plane
8. ISO (film speed)
• Film speed is the
measure of a
photographic film's
sensitivity to
light, determined by
sensitometry and
measured on various
numerical scales, the
most recent being the
ISO system. A closely
related ISO system is
used to measure the
sensitivity of digital
imaging systems.
9. White
Balance
• Color Temperature
of the image.
Setting depend on
the lighting
available.
10. Angle of View
• The area of a scene that
a lens covers or sees.
Angle of view is
determined by the focal
length of the lens. A
wide-angle lens (short-
focal-length) includes
more of the scene-a
wider angle of view-
than a normal (normal-
focal-length) or
telephoto (long-focal-
length) lens. [What the
lens sees, kind of like
what you see when you
look at something]
Hinweis der Redaktion
Relatively insensitive film, with a correspondingly lower speed index requires more exposure to light to produce the same image density as a more sensitive film, and is thus commonly termed a slow film. Highly sensitive films are correspondingly termed fast films. In both digital and film photography, the reduction of exposure corresponding to use of higher sensitivities generally leads to reduced image quality (via coarser film grain or higher image noise of other types). In short, the higher the sensitivity, the grainier the image will be.