JVC TK-1280E - Page 18

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
uiedegabeteteiato
With a fixed-focus lens
@ Fully open the aperture and set the focus ring to “co” (infinity).
e In the case of an auto-iris lens only, shoot a comparatively
dark object so that the aperture is open.
@® Turn the FOCUS screw to focus with a screwdriver.
Caution:
e 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 2000 times the focal length of the lens away
from the front of the fens. (For example, if the focal
length is 7.5 mm, the object should be more than 15 m
away from the camera.)
Lens that can be used
@ The TK-1281EG can use 1/2”, 2/3” or 1” video camera C-
mount lenses when the C-mount adapter (standard accesso-
ry) is installed. When removed, 1/2" video camera CS-mount
lenses can also be used.
@ Use a suitable lens for the required area of view. The area of
view for different focal lengths can be obtained using the fol-
lowing formulae. (Use as reference data, when the distance
between camera and object is more than 100 times the focal
length.)
In the case of using a 1/2" lens
Height of the _ 4.8 x Distance between camera and object (m)
area of view (m) Focal fength of lens (mm)
Width of the i“ 6.4 x Distance between camera and object (m)
area of view (m) — Focal length of lens (mm)
16
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.
@Turn 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.)
Notes:
e Use video-iris lenses powered by DC 9 V-10 V with a
power consumption of 50 mA or less.
@ Lin the illustration below should be as shown in the fol-
lowing table. If L exceeds the value in the table, it may
damage the inside of the camera and correct mounting
may be impossible; never use such lenses. Be sure not
to attach the C-mount adapter when using a CS-mount
lens.
Recommended
fearon [tame Rengetec
L C-mount 17.526 Less than
(ee lens* mm 9mm
f CS-mount Less than
«Lens fens** 4mm
Flange-back + with the C-mount adapter attached.
** With the C-mount adapter removed.
e Lenses designed for colour video cameras are recom-
mended. Lenses designed for B/W cameras may have
inferior colour reproduction and picture quality. In partic-
ular, they are not suitable for use outdoors or in very
bright conditions. When using a lens with an ND filter
attached, shooting may not be possible with the mini-
mum required illumination specified.