JVC GY-DV500 Shooting the Screen Image on a Computer Monitor, Gain Sensitivity Adjustment

13. FEATURES OF THE CAMERA SECTION

13-3 Shooting the Screen Image on a Computer Monitor

13. FEATURES OF THE CAMERA SECTION

13-4 Gain (Sensitivity) Adjustment

Outline

The gain should be switched when the brightness is insufficient due to poor lighting conditions.

Band

Video monitor

FILTER

		ALARM
		MONITOR
	GAIN OUTPUT	WHT.BAL
VTR

NG POWER

SHUTTER dial

- - - OPERAT		I ON - - -
SCENE	F I L E	A
SHUT TER		: VAR I ABL E
FAW		: NONE
GA I N L		: 0 dB

The following operation allows the alignment of the shutter speed of the camera with the variable scanning rate of a computer monitor or display.

When a computer monitor screen or display is shot with the camera, a bright horizontal line indicating excessive exposure is displayed in cases when the scanning rate of the monitor is faster than the shutter speed of the camera. A dark horizontal line indicating insufficient exposure is displayed in cases when the monitor's scanning rate is slower than the camera's shutter speed.

The scanning frequency of a monitor varies due to various reasons during the computer operation. Adjust the scanning rate to obtain a stable image while observing the image in the viewfinder.

Variable Scan [V.SCAN]

•Basic operation

Set the SHUTTER item on the OPERATION MENU screen to VARIABLE. Then move the SHUTTER knob upwards or downwards to change the shutter speed.

(The speed is displayed on the viewfinder screen.)

•Compatible frequencies

The variable scan function is compatible with scanning frequencies in the following range.

60.1to 2084.6 Hz (U-ver.)

50.1to 2067.8 Hz (E-ver.)

CAUTION:

GAIN SWITCHING

GAIN switch

AUTO IRIS	FULL AUTO BLACK					LOLUX
BACK L				STRETCH
NORMAL				NORMAL
SPOT L				COMPRESS
			ON	E		B
	L	AM		KNE		T
STBY	M	BARS	O	AUTO		PRS
	H		FF
AVE		OUTPUT			WHT.BAL
S	GAIN
VTR

NG POWER

ONOFF

CAUTION:

When gain is set to "ALC", gain is boosted automatically as the illumination becomes darker. However, noise will increase a little because the screen becomes brighter as the ALC (Auto Level Control) function boosts the gain more than in the case of manual adjustment.

This switch allows the gain to be boosted when the illumination of the subject is insufficient.

Switch Position	Factory-Set Gain
L	0dB
M	9dB
H	18dB

When the GAIN switch is switched, the newly set gain is displayed for about 2 seconds on the Status 0 or Status 1 screen in the viewfinder.

Set it to L (0 dB) in normal use.

The gain set for each of the switch positions can be changed with "GAIN" on the OPERATION MENU screen.

It is also possible to use the ALC function that varies the gain automatically.

☞See page 73 for details.

To make the gain transition smoother, set “SMOOTH TRANS” on the OPERATION MENU to “ON”.

☞See page 73.

However, note that the SMOOTH TRANS function is not available if gain is set to ALC.

GA I N	M	: 9 d B
GA I N	H	: 1 8 d B
SMOOTH TRANS		: OFF
PAGE BACK

This function is not compatible with slow-speed computer monitors with a vertical scanning speed of 60 Hz (U-ver.)/ 50 Hz (E-ver.).

GAIN BOOST UNDER LOLUX CONDITION

LOLUX on/off button

OPERATION MENU screen

AUTO IRIS	FULL AUTO BLACK					LOLUX
BACK L				STRETCH
NORMAL				NORMAL
SPOT L				COMPRESS
	L	CAM	N	KNEE		B
			O			A
STBY	M	BARS	FF	AUTO		PRST
			O
E	H				WHT.BAL
S
AV		OUTPUT
VTR	GAIN

NG POWER

ONOFF

The LOLUX button is used when the illumination is still insufficient after compensating with the GAIN switch.

Press the button to enter the LOLUX mode in which the gain is boosted by about 33 dB.

"LOLUX ON" is displayed for about 2 seconds on the Status 0 or Status 1 mode screen in the viewfinder.

Pressing the button again cancels the LOLUX mode. "LOLUX OFF" is displayed for about 2 seconds.

When the LOLUX function is in use, the image definition on the screen will degrade to increase residual images, but this is not a malfunction.

81

[Relationship between gain, iris and shutter]

0.7 Lx		8 Lx		32 Lx		2000 Lx		4200 Lx	18000 Lx
					FULL AUTO SHOOTING
								1/60 (U-ver.)	1/240 (U-ver.)
33 dB		12dB		0 dB				1/50 (E-ver.)	1/200 (E-ver.)
	LOLUX		ALC		AUTOMATIC IRIS				EEI
				F1.4			F11	F16

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