Adjusting The White Shading - JVC GY-HM750CHU Instructions Manual

Shooting
Adjusting the White
Shading
You need to adjust white shading when you change the lens.
Even if white balance is adjusted in the center of the screen,
the top and bottom of the screen may not be adjusted.
In this case, green and yellow colors may appear on the
screen. This is due to the characteristic of the lens. Correcting
this phenomena is known as white shading adjustment.
Perform this adjustment after adjusting the white balance.
1
Fill the monitor screen with a pattern box of uniform
light source or white (plain) paper shone with uniform
lighting.
2
Set the control of the camera lens as follows.
A
Set the aperture to F4 or more such that the iris
achieves optimum brightness.
If the brightness is insufficient even at F4, set to the
optimum brightness by increasing the lighting.
B
When using a zoom lens, set to the center of the zoom
adjustment range.
3
Adjust the white balance of the camera recorder.
( A Page 42 [Memory A Mode (A), Memory B Mode (B)])
4
Set the chroma level of the monitor to the maximum.
5
Check the monitor screen.
● There is no need for adjustment if there is no color at the
top and bottom of the screen.
● If the top of the screen is greenish and the bottom is
reddish or vice versa, continue this adjustment.
6
Adjust the white shading.
It is recommended to adjust only G (green).
A
Set [Main Menu] B [Camera Process] B [White
Balance] B [Shading Mode] to Manual . (A Page 85)
B
Select [Adjust] in the [White Balance] menu and press
R
the Set button ( ).
[MENU] Button
Cross-Shaped
Memo :
Button (JK)
Set Button (R)
7
screen.
8
Note :
C
Select the item to change with the cross-shaped button
JK
( ) and press the Set button (
D
Change the setting value with the cross-shaped button
JK
( ) while looking at the evaluated value at the bottom
right of the LCD monitor or viewfinder screen.
● If the evaluated value of the adjusting channel is larger
than 0, use the cross-shaped button (
setting value so that the value is more or less Even .
Similarly, if the value is smaller than 0, use the cross-
J
shaped button ( ) to change the setting value.
( A Page 44 [Evaluated value:])
[R]
[G]
[B]
(Adjustment range : Min (-128) to Normal to Max (127))
● There may be some delay in the changes of the evaluated
value after pressing the cross-shaped button (
● Increasing the setting value suppresses the colors at the
bottom and enhances the colors on top.
E
Press the Set button (
changes are complete.
F
Select [Back] and press the Set button (
the [White Balance] menu.
Top
Btm
Evaluated Value Detection Frames
Press the [MENU] button to return to the normal
Readjust the white balance. (A Page 42)
● If the lens setup is incorrect, you may over-correct the
white shading. Set to the recommended settings for the
lens. (Do not open the iris more than F4. Do not adjust the
zoom lens at the telephoto or wide angle end.)
● White shading occurs as a result of the optical
characteristic of the attached lens. This is not a camera
malfunction.
Evaluated value:
A value that compares the average values of the R, G, B
channels in the evaluated value detection frames at the top
(Top) and bottom (Btm) of the LCD monitor or viewfinder
(difference between [Top] and [Btm]).
If [Top] is larger than [Btm], a negative value is displayed. If
[Top] is smaller than [Btm], a positive value is displayed.
When there is no difference between [Top] and [Btm],
Even is displayed. Set such that the evaluated value is
more or less Even .
R
).
K ) to change the
Red adjustment
Green adjustment
Blue adjustment
JK
R
) to save the settings after the
R
) to return to
C D
F
Evaluated Value
).