Magic Lantern for copying super 8 and standard 8 home movies

Started by Oddball, March 05, 2013, 12:44:05 PM

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Oddball

ML has very many marvellous uses.  I wondered if it might help me with a long-standing problem.  I have a large collection of home movies shot in super 8 (and a few in standard8).  I've wanted for ages to digitize them so I can bring them into 21st-century technology, but copying to a video camera produces horrendous flicker, and the cost of professional frame-by-frame is prohibitive.  The answer proved to be a very simple 'yep' with the aid of my ML-equipped Canon 5D mk II.  All I needed was to set ML to record the projected images at 18 fps on a 24 fps background.  The result is a brilliantly smooth copy with no flicker (and played back at 24 fps).  Thanks a lot, ML!

g3gg0

thanks for the information.

hmm, but i dont get the idea of recording 24fps footage at 18 fps to get it flicker free and then playing it back at 24 fps.
i assume the 18fps undersamples the footage and thus prevents the flickering, but then playing back at 24 fps accelerates the playback?
did you resample it to 24 fps again?
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Nolleos

Quote from: Oddball on March 05, 2013, 12:44:05 PM
... All I needed was to set ML to record the projected images at 18 fps on a 24 fps background. ..

What do you exactly mean by this. Can you explain it further, as I am interested to use this method also to copy my 8 mm movies.

Ton

Oddball

OK, here's a follow-up and a response to the two reply posts...

By 'flicker', I'm talking about the horizontal ghost bands that move up and down the image as you watch 18 fps 8 mm footage filmed at a non-matching speed.  When you use ML film at a speed other than the standard (24/25/29.976/30 etc. fps) you are still shooting on the background of that standard speed.  So g3gg0 is quite right.  The camera records the file and plays it back at the standard speed, not at the speed you set for filming.  That's why the use of slower frame rates in ML is really intended for achieving time lapse effects: when you play back, things are sped up.

I happen to be using 24 fps as the camera set speed.  If I play back the 18 fps footage as shot, it's sped up by a factor of 1.33-fold.  So I edit everything with Adobe Premiere Pro and adjust the speed of each clip to 75% (=18/24).  Premiere then slows everything back to the equivalent of its original shooting speed but the use of 18 on 24 in the camera has eliminated the flickering bands.  If you don't have editing software that can change the digital frame rate your footage will indeed look sped up.

I've now copied a lot of my old 8 mm movies.  At one stage the flicker reappeared and I discovered by experimentation that was because the projector had suddenly decided to run a tad faster.  Thanks to ML (and some patience and some cussing) I was able to restart copying at 18.62 fps.  (Then I reset the clip speeds to 77.6% in Premiere Pro!)

Some years back I paid for a couple of professionally made copies from super 8 and was far from pleased with the results.  They were mostly flicker-free (though it reared its head in places) but poorly lit.  This is a definite limitation with copying: you need a projector with a strong lamp or you're unlikely to get a bright result.

While I remain mostly pleased with the results I've got, I have one problem to overcome.  When the film shows something moving fast the 24 to 18 frame rate correction in Premiere interpolates a kind of double exposure effect, picking up bits of neighbouring frames to compensate for the slowing down process.  It seems to do this whether a clip is or is not marked for 'frame blend'.  If anybody knows a way to get the 18-on-24 footage slowed down without interpolation, please shout!

The 'ghost motion' effect created by software frame interpolation is something I find much easier to live with than the horizontal band flickering.  I've uploaded to YouTube a short sequence of old movie filmed in a zoo so you can see the final product at http://www.youtube.com/watch?v=qvk3lySWWc4&feature=youtu.be.  (I haven't cropped the film properly; that's not the issue.)  The ghosting effect is apparent in a few places, but in general I'd say this result is almost as good as the best you can get with computer driven frame-by-frame copying using complex pulldown algorithms to match the speeds.

Francis

You can conform the file from 24fps to 18fps. I don't know how with Premiere but you can with the Cinema Tools program that is bundled with FCP7.

Oddball

Thanks: but I'm on Windows not a Mac!  Theoretically I should be able to do the same thing with After Effects and Premiere, but I'm not convinced the latter ever really conforms speeds without creating the strange blended frames, whether or not blending is ticked.  Clearly I need to experiment further.

Oddball

Urgent update!

I find I'm maligning Adobe Premiere unreasonably.  The motion ghosting is my own fault.  I'd set the ML shutter speed to 1/21 to maximize light input.  It was this setting that was allowing the 8 mm frames to double expose!  I'd assumed that a shutter slightly faster than 1/18 should be fine for for film projected at 18 fps, but of course each frame is actually shown for less than 1/18th of a second so the shutter speed needs to be faster to avoid the possibility of (faint) double exposure effects.  I've now recopied some movies at a shutter speed of 1/35 without problems.

FWIW; also when you change the speed or duration of a clip in Premiere this results in the video being conformed properly (occasional frames duplicated at intervals appropriate to the speed change).  Interpolation of blended frames only happens when this feature is positively selected.

Apologies for causing confusion!