Canon EOS 20D Digital, Руководство по обслуживанию

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1.5 Viewfinder
1) Viewfinder optics
The basic configuration of the viewfinder optics is the same as the EOS 10D's.
Only the pentaprism and eyepiece optics have been optimized so that the
viewfinder magnification is slightly better (from 0.880 to 0.90).
The other specifications (95% coverage, 20mm eye point, dioptric adjustment
range from -3.0 to +1.0 dpt) are the same as the EOS 10D.
The dioptric adjustment mechanism is based on the EOS 10D's. However,
since the movement of the lens during dioptric adjustment is larger, the -3.0 to
+1.0 dpt range is retained even while the effects of the moving lens' inclination
and eccentricity are reduced. Thus, even when there is dioptric adjustment, the
eyepiece optics still make it easy to see.
2) Superimposition display
The newly-developed superimposition
display optics have been incorporated. The
light from the superimposition LED
positioned on the upper rear of the
pentaprism goes through the SI prism and
pentaprism. Then it is projected in the
configuration of the AF points on the fine
reflective surface of the acrylic reflective plate
between the pentaprism and focusing screen.
This is how the SI illumination is produced.
Technical Information
14
Metering sensor
Metering lens
Eyepiece lens 1
Eyepiece lens 2
Eyepiece lens 3
LCD prism
LCD
Large color LCD
Imaging base board
Secondary mirror
AF sensor
45 main mirror
Focusing screen
Pentaprism
Built-in flash
Image sensor
AF mirror
Secondary image-formation lens Infrared cut filter
Acrylic reflective plate
Shutter
Fig. 022 Cross section at center.
SI-LED
SI prism
Fixed diaphragm
Acrylic reflective plate
Pentaprism
Fig. 023 SI optics