12. FEATURES OF THE CAMERA SECTION 12-4 Shooting the Screen Image on a Computer Monitor

 

12. FEATURES OF THE CAMERA SECTION

12-5

Gain (Sensitivity) Adjustment

Outline

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

Band

Video monitor

POWER VTR

SHUTTER dial

 

––– CAMERA OPERATION –––

SHUTTER

VARIABLE

FAW

A

GAIN L

0dB

GAIN M

6dB

GAIN H

9dB

LOLUX GAIN

30dB

SMOOTH TRANS

OFF

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 or LCD monitor.

Variable Scan [V.SCAN]

Basic operation

 

Set the SHUTTER item on the CAMERA OPERATION menu

 

screen to VARIABLE. Then rotate the SHUTTER dial upward

 

or downward to change the shutter speed.

 

(The speed is displayed in the viewfinder or LCD monitor.)

Compatible frequencies

 

The variable scan function is compatible with scanning

 

frequencies in the following range.

 

60.1Hz to 2084.6 Hz

CAUTION: This function is not compatible with slow-speed computer monitors with a vertical scanning speed of 50 Hz.

GAIN SWITCHING

 

 

GAIN switch

 

 

AUTO IRISFULL AUTOBLACK

 

LOLUX

BACK L

STRETCH

MODE

VTR

NORMAL

NORMAL

 

SPOT L

CAM

POWER VTR

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 3 seconds on the Status (0, 1, 3) screen in

the viewfinder or LCD monitor.

 

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 CAMERA OPERATION menu screen.

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

A setting at –3dB corresponds to a decreased sensitivity equivalent to the brightness of a 1/2 filter.

See page 69 for details.

The gain transition can be made smoother by selecting “SMOOTH TRANS” on the CAMERA OPERATION menu screen.

See page 69.

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

SPOT L/BACK L

MIDDLE

ASPECT RATIO

4:3

PAGE BACK

 

GAIN BOOST UNDER LOLUX CONDITION

The LOLUX button is used when the illumination is still

CAMERA OPERATION menu screen

 

 

LOLUX on/off button

AUTO IRIS

FULL AUTO

BLACK

 

LOLUX

BACK L

 

 

STRETCH

MODE

 

 

VTR

NORMAL

 

 

NORMAL

SPOT L

CAM

POWER VTR

ONOFF

insufficient after compensating with the GAIN switch. Pressing the LOLUX button again will enter the LOLUX mode. The gain up value during the LOLUX mode is set in LOLUX GAIN of the CAMERA OPERATION menu. “LOLUX ON” is displayed for about 3 seconds on the Status (0, 1, 3) mode screen in the viewfinder or LCD monitor. Pressing the button again cancels the LOLUX mode. “LOLUX OFF” is displayed for about 3 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.

Relationship between gain, iris and shutter

 

 

 

0.2 Lx

8 Lx

32 Lx

2000 Lx

4200 Lx

18000 Lx

 

 

 

 

FULL AUTO SHOOTING

 

1/50 (E model)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

36 dB

12dB

0 dB

 

1/60 (U model)

1/240

LOLUX

 

ALC

 

AUTOMATIC IRIS

 

 

EEI

 

 

 

F1.4

F11

F16

 

82

83

Page 43
Image 43
JVC GY-DV5000 Gain Sensitivity Adjustment,  Variable Scan V.SCAN, Relationship between gain, iris and shutter