Canon EOS 50 E - 3.3 FLANGE to FOCAL PLANE DISTANCE ADJUSTMENT

Part 3: Repair Information
3.3 FLANGE to FOCAL PLANE DISTANCE ADJUSTMENT
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I ®' 11 t• 1H The Flange to Focal Plane distance (FFD) must be adjusted when the front I
I . I
I panel unit or mount has been replaced. Before making the adjustment place I
I the focusing rail optical flat on the rails to check for gross misalignment. I
I After adjustment, check the viewfinder focus. I
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PuRPosE:
Adjust the FFD to 44.14mm (with focusing rail optical flat on outer rails).
STANDARD:
FFD 44.14 ± 0.05mm (center of optical flat).
Parallelism: 0.03mm or better (difference in four comers)
Pressure plate center 44.17 ± 0.05mm
(Use this data on the pressure plate center for electric
adjustment AF Standard adjustment.
Pressure Plate Center Depression: 0.030 + /- 0.020mm
using outer rail reference).
*: Pressure Plate Center Depression is measured at the
"E" point.
0
A
B
0
0
E
0
D
C
0
•: E should be lower (more +) than any of ABCD, but
one of the four points can be as much as +15um,and
one more can be +5um compared to E.
Fig. 3-39 Pressure Plate Points
TOOLS:
Dial gage / Auxiliary ring (2mm) / Optical flat / Flange gage (44.14mm or 42.14mm)
PREPARATIONS:
1) Insert the auxiliary ring (2 mm) between the leg of the dial gage and the point.
• This is because the dial gage was designed for the FD lens (42.14mm) standard.
2) Use the flange gage (44.14mm or 42.14mm) and optical flat to adjust the dial gage
to zero.
Dial Gage
Check that small dial
reads as shown and
adjust large dial to zero.
0
44.14mm-Gage
0
42.14mm-Gage
Fig. 3-40 Dial Gage
3-30
~
Optical Flat