Canon EOS 7 Service Manual page 81

Part 2: Technical Information
(3) Key points for high-speed continuous shooting
The EOS ELAN 7 E / EOS 30 has the following features to attain high-speed
continuous shooting. (A few of them have been mentioned previously.)
1) M2 motor for M1 driving transmission switchover
The EOS ELAN II E / EOS 50 E uses the one and only motor for the driving
transmission switchover. Whereas the EOS ELAN 7 E / EOS 30 uses the M2
motor instead of the M1. In the continuous shooting sequence, the driving
transmission switchover need not be executed by the M1 motor. This improves
the continuous shooting speed.
2) Two-speed (High and Low) gear-switching mechanism for film advance
With a two-speed gear in the film advance mechanism, the High gear's gear ratio
has been made small to shorten the film advance time.
3) 32-bit RISC microcomputer for high-speed processing
The 32-bit RISC microcomputer with a standard clock speed of 33.554 MHz
enables high-speed processing.
4) In the continuous shooting sequence, the mechanisms and the predictive lens are
driven simultaneously.
As with the EOS-1V, in the AI Servo AF mode, the lens is driven simultaneously
during all sequences except during the exposure. This increases the continuous
shooting speed and improves the tracking ease of a moving subject during
predictive focusing.
(4) Autoloading and automatic ISO speed setting with the DX code
Basically, it is the same as with the EOS ELAN II E / EOS 50 E. During autoloading,
about 3.5 frames (28 perforation holes) are wound around the take-up spool, taking
about 1 sec. The ISO film speed is read from the film cartridge's DX code and set
automatically within ISO 25 to 5000. The ISO speed can also be set manually within
ISO 6 and 6400. Infrared film cannot be used because it will get fogged by the
camera's infrared photo reflector.
(5) Film rewind
When the frame counter reaches "36" or when the end of the film is reached,
autoreverse begins. During the film rewind, the film perforation continues to be
detected. After the frame counter is "0" and the stipulated time elapses, the motor
stops. If C.Fn-2-1 has been set, the motor stops at a shorter time after the frame
counter becomes "0." This leaves the film leader outside the cartridge.
2-14