Radio-Television-Film - Equipment Tip Sheets

DV TIPS

Visit the College of Communication's DV Lab Web site for more information.

1. Buy Sony-brand tape.

We have had problems mixing tape brands in our decks and cameras. Mixing brands seems to clog the video heads, which then require cleaning, which then shortens the life of the heads. Therefore we are standardizing on Sony tape.

2. Buy the kind without “the chip.”

Sony sells two kinds of DV tape (not counting DVCAM, see below): one with an embedded memory chip and one without it, which is substantially cheaper. Don't buy the kind with the chip. It serves no function with our equipment.

3. DV and DVCAM, what's the difference?

The picture quality (the compression scheme, or “codec”) is identical. The tapes are interchangeable. However, DVCAM is recorded at a 50% faster tape speed. For example, a DV tape labeled “60 minutes” will last 40 minutes in a DVCAM recorder. All current RTF cameras record in “DV” format regardless of which type of tape is used. (Theoretically, Sony's “DVCAM” tapes are a higher-quality-formulation than their “DV” tapes, which can't affect picture quality but might create fewer dropouts. However, the price difference is considerable.) All current RTF decks (Sony DSR-80) can play back “DV” format, but only record “DVCAM” format, regardless of which type of tape is used. (In other words a 60 m. miniDV cassette will record 40 minutes, and won't be able to play back in a DV camcorder.)

4. Don't use LP mode.

Our decks cannot play back tapes recorded in “LP” (or “EP”) mode, the extended-play speed that squeezes 90 minutes onto a 60 minute tape. Recording speed is set in the camera's menu.

5. Don't use 16:9 (widescreen) mode.

(Unless you understand what it does.) This is not true “widescreen.” It's a trick, a digital simulation of the old anamorphic film formats (CinemaScope, etc.) which squeezed the image horizontally during shooting, then unsqueezed it during projection. But since the camera's CCD is still just 4:3, and the NTSC DV format is still just 720 x 486 pixels, you're throwing away an awful lot of picture resolution to accomplish this “trick.” Finally, the Avid Xpress doesn't support 16:9, so you won't be able to unsqueeze it anyhow.

6. What's “movie mode”?

It is also known as “frame mode” or “progressive mode” on some cameras. Instead of capturing 60 interlaced fields (of 240 lines each) per second, like normal NTSC video, a progressive-scanning camera captures 30 complete frames (all 480 lines at once) per second. Some feel the result is more “film-like,” others that it is too “strobey.” Don't use it unless you've tried it out and have seen the results. Also be aware that if you are planning a video-to-film transfer at any point, at present most such facilities strongly recommend not using progressive-scanned video because of the loss of temporal resolution. Talk to some tape-to-film houses before you shoot.

7. How to record color bars: Always record 30 seconds or so of color bars on the head of each tape before shooting.

On the Canon XL-1, put the camera in Full Auto mode (green rectangle) and press both shutter buttons together for 5 seconds. This will give you full field bars. To turn them off color bars, hold both shutter speed buttons again for a few seconds.

The PD-150 has color bar signal access in the menu settings

On the Sony VX-1000, hold PHOTO and the red START/ STOP button while turning on the camera. You will get full field bars. To clear color bars you have to turn the camera off.

8. Don't leave gaps during recording.

In other words, whenever you rewind the camera to view previous takes, be sure to start recording at least slightly before where the last shot ended! If the camera “sees” blank tape when it start's recording, it will reset its timecode to 00:00:00 and make your life hell in postproduction.

9. Treat every timecode reset as a “new tape.”

If the previous warning came too late, and your tape does contain places where the timecode resets to 00:00:00, it's very important when logging or digitizing in the Avid to treat each section of the tape after a reset as if it were a separate tape altogether. In other words, press New Tape and name each “virtual tape” something like “Tape 1-A,” “Tape 1-B,” etc. This way no “virtual tape” ever contains duplicate time code numbers, and when the Avid prompts you to insert a certain “virtual tape” during a batch digitize, you'll be able to easily cue up that particular section on your “real” tapes.

10. Should tapes be blacked?

It is not necessary to “black” a DV tape before recording on it. However, some DV veterans recommend it for two reasons: it lays down continuous time code, protecting you from the TC resets described in # 8; and some think it helps shake loose dust and detritus left over from manufacturing, slightly reducing the risk of dropouts during critical recording. To black a tape, simply press RECORD with the lens cap on, and let the tape run to the end.

11. Symptoms of a head clog:

The video head might be clogged if: A) the screen is divided into large squares, some of which appear freeze-framed; B) half the screen is frozen, while half plays; or C) the tape is playing back at the wrong speed (too fast) and thw words NOT EDITABLE do not appear on the front-panel display. (A miniDV format tape in a DVCAM machine should always indicate NOT EDITABLE.) Ask a TA or tech staffer for a DV cleaning tape.

12. How much room does DV footage take up on my drive?

Drive Capacity

DV Storage Minutes

DV Storage Hours

10GB

45.0

0.8

20GB

90.0

1.5

40GB

181.0

3.0

60GB

272.0

4.5

80GB

363.0

6.1

100GB

454.0

7.6

120GB

545.0

9.1

180GB

818.0

13.6

200GB

909.0

15.2

Visit the College of Communication's DV Lab Web site for more information.

Drive Capacity	DV Storage Minutes	DV Storage Hours
10GB	45.0	0.8
20GB	90.0	1.5
40GB	181.0	3.0
60GB	272.0	4.5
80GB	363.0	6.1
100GB	454.0	7.6
120GB	545.0	9.1
180GB	818.0	13.6
200GB	909.0	15.2