Format, Iso speed, Jpeg – Canon EOS D30 User Manual

Page 132: Red-eye phenomenon, Shutter speed

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Formatting a CF card is the process of preparing the CF card to store image data. Be careful
when formatting a CF card, because the formatting process erases all data stored on the card.

ISO Speed

An index number representing the photosensitivity of silver-halide photo film. This sensitivity
standard is determined by the International Standards Organization (ISO), and is normally
written as “ISO 100”, etc. The higher the ISO speed, the greater the sensitivity to light. Digital
cameras use ISO speeds based on silver-halide photography.


Joint Photographic Experts Group is a file format for compressing and storing color images.
The compression ratio can vary, but higher compression results in greater image degradation
when the file is expanded (restored).

Red-eye Phenomenon

In a relatively dark room, where subjects’ pupils are dilated, the light from a camera flash
passes through the pupil, is reflected by the retina, and causes the subjects’ pupils to appear
red. Red-eye is particularly prevalent when the flash is close to the optical axis of the lens. Use
the following procedure to minimize red-eye:
q Shoot with the Red-eye reduction function turned on. (The red-eye reduction lamp lights

before the picture is taken, causing the pupils to contract and thus minimizing red-eye.)

w Shoot with an EX-series Speedlite. (The light reflected from the flash will not be directed

along the optical axis of the lens, thus minimizing red-eye.)

e Shoot from as close as possible (same effect as w).

Shutter Speed

The camera’s shutter opens for a variable length of time to control the amount of light that
reaches the imaging element. This length of time is called the shutter speed.