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Mounting A Lens; Flange Back Adjustment - JVC TK-1280E Service Manual

Color video camera head

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Mounting a lens
Unscrew the lens mount cap to remove it.
Attach or remove the C-mount adapter depending on
the lens to be used.
e Hi the adapter is attached so tightly that is difficult to
remove, use long-nosed pliers to remove it. Insert the
tips of the pliers into the holes with no threads, then turn
to remove. A screwdriver can also be used, as shown.
Insert M3 screws into the holes so that the screwdriver
has something to grip. (Use the same method when the
adapter and lens are attached too tightly.)
M3 screws
7~
aap
© Attach the lens to the lens mount. Secure it so that it
does not become loose.
lf the lens has an auto-iris mechanism, connect the iris
cable to the VIDEO IRIS connector or DC IRIS connec-
tor.
e
When
installing a video-level-sensing
auto-iris lens,
connect the lens cable to the VIDEO IRIS connector.
e
When
installing a galvanometric
auto-iris lens, con-
nect the lens cable to the DC IRIS connector.
Flange-back adjustment
When a lens is mounted, adjustment of the flange back (the
distance from the lens mounting position to the focal point)
may sometimes be required. Adjust when the correct focus
cannot be obtained with the lens focus ring.
FOCUS screw
With a fixed-focus lens
@ Fully open the aperture and set the focus ring to "so" (infinity).
@ in the case of an auto-iris lens only, shoot a comparatively
dark object so that the aperture is open.
@®Tum the FOCUS screw to focus with a screwdriver.
Caution:
e Do not forcibly tum the FOCUS screw, as it will cause
damage to the camera.
Note:
e@ When focusing, point the camera at an object that is
more than 2000 times the focal length of the lens away
from the front of the lens.
(For example, if the focal
length is 7.5 mm, the object should be more than 15 m
away from the camera.)
©) If the lens has an auto-iris mechanism, attach the auto-
iris cable to the camera via the tripod mounting base
(when the cable is too long).
Notes:
e Read the instruction manual of the lens carefully.
e If the auto-iris tens has a different type of plug, replace
it with the plug provided.
e A cable with a diameter of
2 mm-4.5
mm
can be
secured with the tripod mounting base.
:
e When mounting a lens, it may require adjustment of the
flange-back. Perform adjustment if necessary. See
page 16.
Adjusting auto-iris lenses
Make this adjustment after connecting the camera to a power
source and to a monitor.
@ Set AGC switch to OFF.
® When using a video-level-sensing auto-iris lens:
Adjust the LEVEL control of the lens to obtain optimum pic-
tures.
When using a galvanometric auto-iris lens:
Adjust the IRIS LEVEL contro! of the camera to obtain opti-
mum pictures.
@® Set AGC switch to ON
It is recommended
that the AGC be used in the ON position
after adjusting the video LEVEL control.
15
With a zoom lens
@ Fully open the aperture and set the lens to the maximum
telephoto position. Then turn the focus ring to focus.
@ In the case of an auto-lens only, shoot a comparatively
dark object so that aperture is open.
@ Set the lens to its maximum wide-angle position.
@Tum the FOCUS screw to focus with a screwdriver.
@ Repeat steps © — © until the difference between focusing
positions
© and @ becomes smallest.
Caution:
® Do not forcibly turn the FOCUS
screw, as it will cause
damage to the camera.
Note:
e When focusing, point the camera at an object that is
more than 5 times the minimum focal distance away
from the lens.
(for example, if the minimum focal dis-
tance is 1m, the object should be more than 5 m away
from the camera.)
15

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Tk-1180eTk-1281eg