Supplemental Information - JVC VideoMovie GR-A30 Instructions Manual

SUPPLEMENTAL INFORMATION
What is "color temperature"?
Light is composed of various color components
in different proportions. A relationship exists be-
tween the temperature of a light source and the
color components of the emitted light; as the
temperature rises, the color of the I ight varies
from red, orange, yellow, white to blue in that
order. "Color temperature" is a value that ex-
presses d ifferences in color among light sources,
measured in Kelvin degrees. Bluish light has a
higher color temperature than reddish light.
What is "white balance"?
Making the colors look natural on TV is what
white balance is all about. Because a camera is
not as adaptable as the human eye, if a light
source is reddish, white subjects in that I ight are
recorded as reddish . White balance adjustment
is performed to compensate for color tempera -
ture variations of light so that wh ites are repro-
duced as white. Correct white balance makes all
other colors correct. The G R-A30U can perform
automatic white balance adjustment. How ever ,
if illumination is insufficient, white balance ad-
justment cannot be performed. To obtain cor-
rect colors, therefore, sufficient illumination is
essential.
What is "illuminance"?
"llluminance" (also called 'luminance') is the
intensity or brightness of light, expressed in lux
or foot-candles (fc). The G R-A30U is designed to
provide best pictures under the conditions of a
700-lux (67 fc) illuminance, although shooting
is possible all the away down to 8 lux (0.8 fc).
To obtain good pictures in very bright light, the
use of an ND (neutral density) filter is recom-
mended. (See chart on this page.)
How to get good color pictures
The simplest w ay is to provide sufficient I ight-
ing (close to th e camera's reference illuminance)
and accurately adjust the camera to the color
temperature of that lighting. If light sources of
d ifferent color temperatures are used together,
accurate white balance adjustment is very dif-
fi cult . For exampl e, if natural light is mixed
w ith artificia l light, which is lik ely to occur
next to windows, co rrect col or s of the su bj ect
are difficult to obta in. It is recommended in
such cases that curtains in th e room be closed
to shut out light from outside. Also, when
artif icial lighting devices are used, they should
all have the same color temperature. For exam-
ple, it is recommended that incandescent or
halogen lamps not be used togeth er with fluo-
rescent I ighting.
Color temperatures of various artificial lighting
Type of illumination
Color
temperature
Tungsten lamp for home use 2800 K
Tungsten lamp for photograph ic use
Quartz-halogen lamp
3200 K
Blue lamp for photograph ic use 5000 K
Warm white 3500 K
Fluorescent lamp
White 4500 K
D ay I igh t type
6500 K
llluminance chart
•The values on this chart are approximated to give you a
rough reference.
'O
Unit : Lux (fc)
~
·;;;
Ql
'O
~
100,000-
•Clear sky, mid-Oay, under sun light
;;::
(9 ,300)
(1 00,000/9,300)
0
z
•Clear sky (10:00 a.m. ) under sun light
-
(65,000/6,045)
• Clea r sk y (3:00 p.m. ) under sunl ight
(3 5 ,000 /3,255)
•Cloudy sky (mid-Oay) under sunlight
(3 2,000/2 ,976)
~
•Cloudy sky (10:00 a.m. ) under sunlight
:i
iii
(25,000 /2 ,325)
u
10,000-
·~
u
(930 )
"'
c.
~
•By t he w indow during the afternoon
.E
(3 ,500/324)
Ql
Cl
c
"' 2,000 (190)- • Cloudy sky (on e hour after sunrise)
a:
(2 ,00 0 /1 90)
1,000(94)-
•Clear sky (o ne hour befo re su nset)
(1 ,0 00/9 4)
600(55)- •Co unters at department st ores
(500 - 700/47 - 66)
-
500(47)- •Bowling center (500/ 4 7)
•Office under flu orescent light
(400 - 500/37 - 4 7 )
•Lib rary (400 - 500/ 37 - 47 )
•Direct light of a flashlight at
1 m (3 ft ) distance (250/ 2 2.7 )
'O
100(9)-
•Streetl ights at night
~
(150 - 200/ 13.5 - 18)
·;;;
Ql
80(7 .3 )-
'O
Cl
c
Mi n imum
.c
light ing for
Cl
:.J
an object
15(1.4)- • Cigarette lighter
(at a d ista nce o f 30 cm / 11 .8 in) (15/ 1.4)
10(1)- •Candlelight
(at a distan ce of 2 0 cm /7 .9 i n)
(10 - 15/ 1 - 1.4)
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