Panasonic AJ-HDC27V, AJ- P operating instructions Variable frame rate, Setting the frame rate

Variable frame rate

This camera/VTR enables the frame rate (shooting

speed) to be set from 4 frames/sec. (3.99 Hz) to 60 frames/sec. (59.94 Hz).

Since the 720P/59.94 Hz format is used for recording onto the tape or outputting to the HD SDI OUT connector, users now have the exciting opportunity to create a whole new dimension of moving images with clearer slow-motion images and blur effects—a world which was hitherto confined to the field of film production—in their own video productions.

This unit automatically stores as the tape management information both the frame rate information which indicates the shooting speed and

the active frame information which indicates the first frame where the frame image was switched in the user’s bit of the sub-code track area (this used to be the LTC area). This information is output from the TC OUT connector and HD SDI OUT connector. Further,

the active frame information is stored in the least significant digit of the user’s bit while the frame rate information is stored in its lower third and fourth digits.

Setting the frame rate

1 Perform the menu operations (pages 72 to 74), and display the “FRAME MODE” screen.

n< FRAME MODE >

FRAME RATE RANGE:60-12

FRAME RATE	:24
SCAN REVERSE	:OFF

2 Turn the JOG dial button to move the arrow (cursor) to the “FRAME RATE” item.

3 Press the JOG dial button, and set the desired frame rate.

Turn the JOG dial button to select the frame rate, and press the JOG dial button to enter the selection.

4 Press the MENU button to exit the menu operations.

The setting menu is cleared, and the display showing the unit’s current statuses appears at the top and bottom of the viewfinder screen.

<Notes>

In this unit, the frame rate is set by changing the storage time of the optical signals sensed by the CCD. Depending on the frame rate setting, the following problems may arise.

1White streaks

The dark current of the photodiode that configures the CCD’s pixels causes defective pixels to arise, and this results in the appearance of white streaks on the screen. This current increases in direct proportion to the rise in the CCD’s temperature and storage time in the photodiode.

In short, the white streaks increase in inverse proportion to the frame rate setting.

When a lower frame rate setting is desired, reduce the master gain setting and, where possible, avoid direct sunlight and use the unit in a cool environment.

2Delayed response time in automatic processing

When the frame rate setting has been lowered, it takes longer for the unit to perform the automatic processing (such as auto white balance, flare compensation, auto knee and auto iris), possibly giving the user the impression that something is odd or wrong.

The response time for automatic processes is particularly slow at a frame rate of 20 frames/sec. (19.98 Hz) and below.

When the frame rate has been set to 20 frames/sec. (19.98 Hz) or below, it is recommended that the unit be operated with the automatic processing released.

3Black shading/white shading

Both black shading and white shading are compensated for when the frame rate is set to 60 frames/sec. (59.94 Hz) and scan reverse is set to OFF. No compensation is provided at any other settings.

4Disturbed images

The images may be disturbed for a moment if scene-to-scene continuity is performed while the time code is allowed to advance in the rec run mode when the frame rate is set to 24 frames/sec. (23.98 Hz).

This occurs in order to reset the video signals from the camera so as to maintain the continuity of the time code recorded on the tape.

The disturbed images are not recorded on the tape

but they will affect the signals which are output from the HD SDI OUT connector.

Furthermore, if the time code is allowed to advance in the free run mode when the frame rate is set to

24 frames/sec. (23.98 Hz), at that instant when the time code is preset or the time code is locked to the external signal, the images may be disturbed for a moment.

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