Appendixes
179
Glossary
Focal length
The distance from the middle of the lens to its focal point (in
millimeters). Longer focal lengths result in narrower angles of view
and the subject is magnified. Shorter focal lengths result in wider
angles of view.
Histogram
A graphical representation of the brightness of an image. The
horizontal axis represents the brightness and the vertical axis
represents the number of pixels. High points at the left (too dark)
and right (too bright) on the histogram indicate a photo that is
improperly exposed.
H.264/MPEG-4
A high-compression video format established by international
standard organizations ISO-IEC and ITU-T and developed by the
Joint Video Team (JVT). This codec is capable of providing good
video quality at low bit rates.
Image sensor
The physical part of a digital camera that contains a photosite for
each pixel in the image. Each photosite records the brightness of
the light that strikes it during an exposure. Common sensor types
are CCD (Charge-coupled Device) and CMOS (Complementary
Metal Oxide Semiconductor).
EV Compensation
All the combinations of the camera’s shutter speed and lens
aperture that result in the same exposure.
EV (Exposure Value)
This feature allows you to quickly adjust the exposure value
measured by the camera, in limited increments, to improve the
exposure of your photos. Set the EV compensation to -1.0 EV to
adjust the value one step darker and 1.0 EV to one step brighter.
Exif (Exchangeable Image File Format)
A specification to define an image file format for digital cameras
created by the Japan Electronic Industries Development
Association (JEIDA).
Exposure
The amount of light allowed to reach the camera’s sensor.
Exposure is controlled by a combination of the shutter speed, the
aperture value, and ISO sensitivity.
Flash
A speed light that helps to create adequate exposure in low-light
conditions.