Capturing old 8mm Q

[JonH]

Hi Brian and all,

I have been having great luck making DVDs thanks to all of you on this forum. I don't contribute because I'm still not too knowledgeable about these things.

Anyways, I have a friend with about 50 old 8mm reels of film who wants to put them on DVDs. He can't afford the professionals so he wants to film them with a camcorder. We tried to film some last night and ran into a pulsating problem. The old projector he was using is variable speed and at times we could get the speed just right which resulted in smooth video. But then the speed seemed to change slightly and the pulsating came back. I'm assuming that the projector is defective in that it cannot maintain a consistent speed and we should try to find another one.

Also, I read that an anolog camcorder works better than a digital when trying to avoid pulsations. Is this true? I used a hi-8 camcorder last night instead of my digital camcorder.

Any tips, advice, etc., would be appreciated.

Jon

[KRSESQ]

Hey, Jon.

The reason the image pulsates is because the shutter of the projector cannot synchronize properly with the 30 fps frame rate of the camcorder.

Most commercial movie projectors have a three blade shutter (you can see it spinning if you take the cover off the projector while it's running). The projector is "scanning" each frame of film 3 times during projection. At 18 fps this comes to 54 scans per second. If the projector has variable speed control, you can correct this by adjusting to 'prox' 20 fps, so the 60 scans per second more closely match the 30 fps of the camcorder.

Two problems emerge: first, obviously by speeding up the projector the screen action will be accellerated, to unintentional comic effect. You may be able to correct for this with an editing program like Premiere or MSP, but it will add to the render time.
Second, most commercial movie projectors don't have a really accurate speed control, as you've already discovered. So it's hard to keep the projector in true sync with the camcorder.

The pros use projectors equipped with 5 bladed shutters. This allows better sync with the camcorder (18 fps x 5 scans per frame equals 90 scans per second equals 3 film frame scans per video frame). Of course, they also use a crystal controlled motor to ensure perfect sync with the video.

At the Public TV station where I do pick-up work, we've gotten satisfactory results just shooting the screened movie image. Since then I've been able to put together a more sophisticated rig for digital capture. But with a little adjustment of your technique you should get acceptable results.

Kevin

[JonH]

Thanks for the reply, Kevin. We found a better projector this morning and will try again tonight. I assume we should use the digital camcorder instead of the analog hi 8??
Jon

[KRSESQ]

Definitely. Lots better quality control.

Kevin

[F6BUH]

Maybe I can help somehow...I have a lot of old video cameras
and some are fitted with tube pick-up devices:for instance a
Sony Trinicon HVC3000 (mono tube ) and a JVC KR1900 (3 tubes )
those are 20 years old!Here the point:the sensing devices show
highter lag than CCD and much more, seem to have wider dynamic range,so problems with shutter synch are hidden and
video seems better as contrast is not so hard.I think the loss
in resolution is not important as those 8mm,even super8 movies
are not that crisp!In those old times,Sony and others offer optical devices (mainly a 45 degrees mirror...)that fit righ on the camera's
lenses,maybe you can find one..
DANIEL.

[Brian Ellis]

Very tricky.

Firstly, you don't specify whether it's double-8 16 fps silent or super-8 18 fps silent or 24 fps sound. This makes a big difference.

The ideal tool is a telecine machine. This consists of an ultra fine CRT which has a blank double-raster on the screen. This is focussed by a quality lens onto the film, which is drawn past at constant speed. On the other side of the film there are three photomultipliers with primary filters and dichroic prismatic beam splitters. There is also an optical perforation detector which is used to synch the raster to the frame position. I believe the raster is always at 25 or 29.97 fps and the film is drawn through at the same rate. The conversion from the shooting fps is then done digitally. These machines cost an arm and a leg, which is why pro conversion is expensive, but it is good and jitter-free.

If using the projection technique, Kevin has given some good data. I think it is better to use back-projection (less stray light, no parallax errors) There are some cheap plastic boxes available expressly for this with a ground glass screen and a surface-silvered mirror (for image correction).

You may find it useful to play around with shutter speed, as well.

[JonH]

Thanks for all the advice guys. We just finished capturing 3 hours and the results are acceptable. My father-in-law had a projector with a larger motor and we pretty much controlled the pulsating problem by adjusting projector speed. This was old, silent, regular 8 mm on the 5 minute reels.
Jon