161
Ref
erence
13
Basic Terminology
Aperture
The aperture value (f/number) indicates the size of the
aperture opening in the lens. It is equal to the focal length
devided by the aperture diameter. It adjusts the amount of
light striking the CMOS sensor. The aperture value is
displayed on the camera’s LCD panel and in the
viewfinder. It can range anywhere from 1.0 to 91, depend-
ing on the lens attached to the camera.
Shutter speed
The shutter speed is the length of time the camera’s shutter opens to expose the CMOS
sensor to the light coming through the lens. It adjusts the amount of light striking the CMOS
sensor.
Format
When you format a CF card, it prepares the card to store data in it. It also erases any data
stored on the card. Before formatting a CF card, be sure it has no valuable data.
File numbers and folders
The captured images are automatically assigned a file
number from 0001 to 9999 and stored in a folder that can
contain up to 100 images. The folders are numbered from
100 to 999 and stored in the CF card.
The file name of JPEG images will be “IMG_ “ appended
with the “.JPG” extension. RAW image file names will be
“CRW_ “ appended with the “.CRW” extension. Image file
names with the “.THM” extension are thumbnail image
files for the index display.
Example: IMG_0001.JPG
File name Extension
File number
Firmware
This is software containing various camera control instructions. The EOS 10D uses the
firmware for shooting and image processing.
0001
100
0002
0099
0100
–
–
–
–
0101
101
0102
0199
0200
9901
199
9902
9999
0001
200
0002
0099
0100
.
.
.
