Tuesday, May 31, 2005

Digitize Your Home Movies

Nowadays, working with video on a computer, in the form of digital video, is relatively simple. That may not be much of a comfort, however, if you're staring at several hours of Super 8 film and contemplating digitizing your home movies. Nevertheless, we decided to give this a try, converting the analog footage ourselves, using a prosumer and a consumer DV camera. We also had two service bureaus convert the footage. We discuss the results here.

Let's walk through the process of digitizing video shot on 8-mm and Super 8 film to DV format. During the transfer, you'll use a film projector to display the footage and a DV camera to videotape it. Since most DV cameras can also output DV while shooting, you can transfer the output simultaneously to your computer, eliminating capture as a separate step. You'll need plenty of disk space, as each 50-foot film roll contains 3 to 4 minutes of video and requires about 750MB of storage space (about 13GB per hour of film). If you want to archive the unedited film directly on DV tape, as we did, you'll also need plenty of DV tapes; count on storing about 13 to 15 film rolls per 60-minute tape.

Other requirements include a tripod, a FireWire cable, and a large white posterboard to use as a projection screen. Pick up a power strip if you don't have one handy and a small paintbrush to clean dust from the projector lens. Consider buying a new bulb for your projector as well.

You can speed up the process by consolidating your 50-foot films onto 7-inch reels ahead of time. Each reel holds about 400 feet. At the least, get the film in chronological order, which will simplify editing later. And play one or two films to gauge their condition. If stored properly, even 50-year-old films should be in good condition, but if there is dirt, mildew, or other damage, you'll want to clean that off beforehand.

With the projector off, clean all optical components with glass cleaner sprayed on a soft, clean cloth, or pick up a lens brush at your local camera shop or drugstore. If there is dust or grime in the picture frame, brush it out with the paintbrush, something you'll do frequently during production. If you have to handle the bulb, use cotton gloves or a towel; finger oil can cause the bulb to explode.

Your workroom should be windowless or have drapes that can block all light. Because placement of the projector and camera must be very precise, a concrete floor is preferable to a wooden floor, which can vibrate. You'll need a flat section of a wall for the posterboard, and enough space between your worktable and the wall (about 7-feet in our tests) for the projected image to be about 13 by 10 inches.

Set up the projector so it shoots directly onto the posterboard, and position the camera beneath the projector and as close to it as possible. (We set up the projector on the edge of the worktable and put the camera on a tripod just beneath the projector; see Figure 1 .) Try to set up the projector so you have easy access to the film-loading side, because otherwise you might pull out your back leaning over to thread the film 80 times in 6 hours. Place your computer on the same table, with your mouse near the projector controls.

There are fundamental differences between film and video. Generally, 8-mm film was shot at about 16 frames per second (fps) and Super 8 at about 18 fps. Most home projectors use a three-shutter system, which displays each frame three times. This means 48 on-screen images per second for 8 mm film or 54 for Super 8.

Your DV camera, by contrast, uses two interlaced fields per frame, one containing the odd scan lines and the other containing the even lines. It captures images at 60 fields per second (30 frames per second * 2 fields). Unless you synchronize the film projector and the camera, the resulting video is going to flicker, because some of the fields will catch one of the projector's shutters in operation, and those fields will be darker than the rest.

Even with the DV camera set at a slow shutter speed, you won't see the projector's shutter, because it's moving faster than the camera can capture it, just as you can't see the individual blades in a fast-moving fan. But it will darken the field just enough to produce the flickering effect.

Digitize Your Home Movies

To minimize flicker, set your shutter speed to 1/60 second, and adjust the projector speed to either 20 fps, which produces 60 images per second, or 10 fps, which produces 30 images per second. Most projectors have variable-speed adjusters without defined speeds ( Figure 2 ), so during conversion, you simply adjust the speed until the flicker disappears.

If you can't set the shutter speed of your camera manually, you may want to rent or borrow one with this capability. Otherwise, the conversion may not be worth doing, as the flicker will be too distracting.

Setting white balance is critical. Different light sources have distinct color temperatures, which highlight certain colors when illuminating a scene. White-balance procedures vary from camera to camera but typically involve zooming in to a white object until it fills the screen and then pressing the appropriate control. This tells the camera that the object is white, allowing the camera to correct for the lighting.

If your camera has manual white-balance controls, set the white balance with the lights off and the projector running with no film, simply projecting a white image against the posterboard. If it doesn't, set the white balance to indoors or incandescent, even if the film you'll be converting was shot outdoors; even though the landscape in the film may have been sunlit, the predominant light in the image you're actually recording is produced by the tungsten incandescent bulb in the projector.

Exposure settings regulate the amount of light that enters the lens. Most camcorders have both manual and automatic controls. We tested manual mode but found it difficult to make the frequently required adjustments without shaking the camera, so we used automatic exposure for all conversions and got good results.

Digitize Your Home Movies

We used manual focus, since autofocus would have attempted to adjust for fuzzy images on-screen. To get set up for the best focus, we hung an image with text on the posterboard before shooting, then zoomed in tightly and focused on the text ( Figure 3 ). Luckily, on most video cameras, zoom doesn't affect focus, so zooming out later to fit the projected image in the camera frame won't make it go out of focus.

Unless you move your camera or projector, the camcorder shouldn't lose focus. If the video you're capturing appears out of focus, adjust the projector, not the camcorder. Once the projector is in focus, changes in the film won't affect focus unless machine vibration somehow shakes the lens out of place.

These tips are easy to forget when you start capturing fuzzy images and grab every focus adjustment within reach to attempt to correct the problem. Remember that older film cameras didn't have autofocus capabilities, and often the film itself was simply out of focus.

To frame the video, shut the lights off and start the projector with no film, displaying a white box on the posterboard. Adjust your camera on the tripod until the white box is centered in the LCD panel, and then zoom in until the projected image fills the LCD.

Digitize Your Home Movies

Start your capture software and watch for black bands around the video, as in Figure 4 . Note that while the television screen is completely full, the same video in Adobe Premiere's capture screen shows a black band on all four sides. These result from fundamental differences between how televisions and computers display video. When framing the video, if you zoom your camcorder in so the video just fills the LCD panel (which generally has some overscan), you'll leave the black band around the video.

This is fine if you're creating a DVD to display on a television set, since the black band won't be visible. If, however, you'll be watching the videos from your computer, the band will show. The only way to monitor the overscan is to capture the image to a computer while you're filming. Otherwise, you simply won't see the overscan.

Once the camera and projector are set up, it's time to run through the process and work out the kinks. Start with a small (50-foot) roll, because you'll likely have to run it several times to get everything right. Thread the film, but before turning on the projector, find the focus and speed adjustments. Then start the projector and focus the video image. Once the image is sharp, watch the camcorder's LCD panel or the computer capture screen for flicker.

Be careful when handling the camera and projector as you start and stop playback and rewinding. Even modest jolts to either device can destroy your careful framing. Also watch for dust in the lens, and brush it out between reels when it starts to accumulate. Once you get through your first four or five rolls, you'll settle into a pleasantly efficient routine that will quickly carry you through to the end of the project. Grab some popcorn and a soda, and enjoy the show.



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We tested with two Sony DV cameras: the DCR-VX2000, a three-CCD prosumer model, and the one-CCD, consumer-oriented DCR-HC40. After capture, we color-corrected the footage using Pinnacle Studio's automatic color-correction filter.

Video Quality 2

We also sent the same film to two high-end service bureaus, Cinepost and Movi-eStuff. Cinepost uses a Rank Turbo conversion system with a "WetSystem" telecine process that places fluid on the film during conversion to fill scratches and other irregularities, and then dries the film before winding it back to tape. After conversion, Cinepost adjusts color with a DaVinci color-correction system. MovieStuff is both a conversion house and a manufacturer of film-to-DV conversion systems. MovieStuff used their own DV8 Sniper unit to convert our footage, then color-corrected the footage on the computer, using a Matrox editing system running Adobe Premiere.

Both companies supplied us with DV tapes, which we captured using Adobe Premiere. We grabbed the same frames from all four sources and compared the quality. A representative sampling of frames is included here.

Video Quality 3

As shown in Figure 1 , Cinepost's WetSystem process excels at removing scratches from film to produce wonderfully clear images. If large sections of your film are scratched, you won't be able to come close to that quality doing it yourself or sending it to a service bureau that doesn't have a similar system. This image was the best case for Cinepost and the worst case for MovieStuff; their output was much closer in all other comparisons.

As you can see in Figure 2 , both service bureaus produced noticeably clearer images than the two cameras, though the differences are generally subtle and would only be obvious when viewing side-by-side comparisons. You won't be able to duplicate the quality that these service bureaus produce, but you can produce fairly impressive results.

Not surprisingly, the VX2000 proved superior to the consumer camcorder, though the differences were subtle. The HC40 showed a hint less detail and slightly less contrast than the VX2000. Figures 3 and 4 are good examples of this.

Video Quality 4

Our only complaint about the HC40 was that we couldn't set the shutter speed to 1/60th of a second, since the camera only supported 1/30 of a second or slower. This forced us to speed the projector up to much faster than real time to eliminate the flicker. We much preferred the more leisurely pace produced by the VX2000 and the service bureaus.

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