Canon EOS 50 E - Page 58

Part 2: Technical Information
2) Phase Determination
Phase detection is performed by the mechanical cam lever on the charge cam gear and
the cam gear phase contacts contacting the phase pattern (CMSPl, CMSP2, CMSP3)
sending the phase signal to the motor, which operates in the clockwise direction.
Flash pop-up
Phase
(Home Position)
Mirror Up
Mirror Up Phase
Mirror, Shutter Charge
Wind Phase
Rotation
Fig. 2-13 Phase Circuit Board
3) Silent Film Transport
Rewind Phase
The basic construction is the same as with the EOS 100 /Elan. Like the EOS Elan, the
motor is controlled through pulse width modulation (PWM) even for film rewind. As a
result, film rewind is ultra-silent.
Although this might be repetitious, the features are as follows:
Q) Careless motor: Smooth rotation with little vibration and operation noise.
® Film advance timing belt: The rubber's anti-vibration properties greatly reduce
film advance noise.
@ Film rewind timing belt: The rubber's anti-vibration properties makes film rewind
noise very soft.
© Film transport unit's floating support: The rubber's anti-vibration properties pre-
vent the film transport unit's vibration from resonating noise through the body.
® Ultra-silent film rewind with PWM control: The motor's low-speed control keeps
noise very low.
Due to the above features, film advance noise is 55 dB and silent film rewind is 42 dB
(as with the EOS 5/A2E). In the fast film rewind mode, it is 42 dB (as with the EOS
100/100/elan). Thus, film transport is very silent.
Figure 2-14 shows the film rewind system's silencing technology.
4) Autoloading, DX Code and ISO Film Speed Setting
Same as with the EOS 5/ A2E.
2-14