Transfer of old (8mm) films to DV

Discussion in 'Video Cameras' started by Matej Artac, Oct 16, 2004.

  1. Matej Artac

    Matej Artac Guest

    Hello,

    I am going to post a few questions, but don't laugh too hard if they turn
    out to be silly.

    I have been thinking of transferring the collection of old, I think they are
    8mm, films my grandfather has somewhere in his attic. Since the films
    consist of a series of "slides" I first asked if there is a tehnique akin to
    scanning the slides and negatives from ordinary still cameras, but he said
    people just point a camera at a white screen and project the films in an
    ordinary fashion.

    Now, if I want to do that, are there any peculiarities I should be careful
    about? I guess the frame rate of those films aren't the same as the
    framerate of my PAL camera, but lower. Since those old projectors probably
    work by exposing the screen with the image for an instant of time, and then
    shut the light beam until the next frame is aligned, will I experience any
    flickering? Should I somehow extend the exposure time on my video camcorder?

    See, these are the kinds of issues that have been boggling my mind ;)

    Matej
     
    Matej Artac, Oct 16, 2004
    #1
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  2. camcorder?

    I've done it reasonably successfully quite recently.
    I used my Sony TRV22E filming the projected image, on a piece of white A4
    paper, from a Bolex 18-5 projector, running at 18fps. I started by letting
    the camcorder auto-focus on a black vertical line in contact with the A4
    paper screen. I then went to manual focus without changing anything. I
    used the TRV22E's Slow Shutter mode set to 1/25s, and this removed the vast
    majority of any flicker. (It didn't remove jumpy images caused by poor
    sprocket holes on the film.) Using Slow Shutter stopped the camera's
    Auto-exposure hunting. I experimented with Manual Exposure, and there's no
    doubt that some scenes could have been better with more attention to that
    sort of detail, but overall I'm quite pleased with the results. They're
    good enough to show the difference in colour saturation between Kodachrome
    (quite good) and Agfacolor which in my Canon 318M turned out somewhat
    under-saturated.
    Discovered that the projector lamp in my Bolex 18-5 wasn't optimally
    positioned - so either modern bulbs are different to the originals, or it's
    been wrong for 30 years. ...and there was varnish on the adjustment screw
    threads.

    Query ... to capture the noise of the projector or not? I've tried it both
    ways.
     
    Malcolm Stewart, Oct 16, 2004
    #2
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  3. Matej Artac

    Jukka Aho Guest

    Yes. Use a tripod (of course!), disable steadyshot (it will go
    haywire with flickering, projected images), switch to manual
    focus. You will probably also want to set up exposure and white
    balance manually.

    After having captured it all, use Avery Lee's VirtualDub and
    Donald Graft's Antiflicker filter to get rid of the flickery
    quality of the images.

    There is also another filter for compensating the uneven
    brightness of the screen caused by the projector bulb
    (the center of the screen is usually brighter than the
    edges), but I forgot its name. It can probably be found from
    Donald Graft's filter collection. (I think you need to shoot
    the screen without running any film to get a mask image for
    this filter.)

    The there is the Deshaker filter (for VirtualDub as well)
    which can be used for stabilizing the frames which jump
    around because of the uneven registration of the sprocket
    holes.

    VirtualDub can be found here:
    <http://www.virtualdub.org/>

    Donald Graft's filter collection is available here:
    <http://neuron2.net/>

    The Deshaker filter lives here:
    <http://biphome.spray.se/gunnart/video/deshaker.htm>
     
    Jukka Aho, Oct 16, 2004
    #3
  4. Matej Artac

    Matej Artac Guest

    How does the result look? What I'd like to know is, with a 25Hz sampling of
    an 18Hz pattern, you get 28% of overlap. So how does that appear on the DV?
    Do you get empty frames? Frames that contain two target frames? Duplicated
    frames don't seem possible.
    Great tips! Thanks!
    I suppose this can be mended to some point by compensating from a ground
    truth (an empty, white screen), though it only goes up to a certain point.
    I know I'll record my grandfather's comments :) But that can always change
    during the post-process.

    Matej
     
    Matej Artac, Oct 18, 2004
    #4
  5. Matej Artac

    Matej Artac Guest

    Good points. I don't think I'd have thought of that, and it can be pretty
    easy with the white screen.

    Matej
     
    Matej Artac, Oct 18, 2004
    #5
  6. Prompted by your comments, I've just hooked up my TRV22 to my PC with the
    FireWire cable and looked at some of the cine captured as described earlier,
    frame by frame. Surprisingly, the image is rock steady and that's across
    the whole of the frame - there's no hint of the 28% overlap. (Don't ask
    why!) However, where the cine film was dusty, specks of dust appear twice.
    On one frame they appear in full contrast against, say, a sky background,
    and on the adjacent frame the speck of dust is ghosted. The ghosted frame
    can be prior to or after the full contrast frame. I imagine that I could
    possibly capture adjacent frames as jpegs, but that will have to wait as I'm
    away for a few days. (Any hints? Can the camera capture adjacent frame by
    frame to the Memory Stick?)
    I tried various colour balance settings, and whilst Auto seemed acceptable,
    I think I used the Outdoor setting as giving the most pleasing result on my
    films. (Guess the Indoor setting should have been more accurate.)
    I captured with the Super Steady Shot active, even though I was using a
    tripod - didn't even think of disabling it! As it operates on the captured
    image and doesn't use motion sensing gyros, it might (?) have compensated
    for wobble in the original cine? There's still plenty of wobble, though!
     
    Malcolm Stewart, Oct 18, 2004
    #6
  7. Matej Artac

    Jukka Aho Guest

    Dunno about "Super" Steady Shot, but at least the Steady Shot on
    the 1st generation D8 camcorders gets completely confused when
    shooting projected images. (It seems to adjust the shutter speed
    as well, and the image starts wobbling, fluctuating and flickering
    cyclically, in a very distracting way. After switching Steadyshot
    off everything gets much better.)
    At least the Steadyshot implementation on the 1st generation D8
    camcorders uses vertical and horizontal velocity sensors inside
    the camcorder to aid the stabilisation. (The service manual lists
    these parts and explains how they can be replaced and calibrated.)
     
    Jukka Aho, Oct 19, 2004
    #7
  8. Matej Artac

    Matej Artac Guest

    I think the best way to do this is to capture the clip using a Type-2 DV
    AVI, then use VirtualDub or alike to output individual frames.
    With the camcorder, the only way I see it is to repeat the "Photo" - "Next
    Frame" procedure, but oddly enough, what you get on the Memory Stick is a
    640x480 image.
    Ah, I thought the positioning of your light bulb resulted in an uneven
    illumination. If that was the case, then you would shoot a projection when
    no film was in the projector, and use this as a mask to correct the rest of
    the frames, as Jukka Aho in reports. Otherwise, of course, the measured white value should be good.
    I think the TRVs and other Sony MiniDV camcorders use the surpluss of the
    sensor pixels to do the image steadying - they somehow (using a correlation
    possibly) estimate the displacement of the overall scene and then readjust
    the virtual frame offset. Therefore no camera motion is required to trigger
    the wobbling, and also no part of the camcorder moves in the process.

    Matej
     
    Matej Artac, Oct 19, 2004
    #8
  9. Matej Artac

    Jukka Aho Guest

    Here are direct links to the actual filters I was referring to in
    that message:

    Antiflicker filter:
    <http://neuron2.net/flick.html>

    Hotspot filter:
    <http://neuron2.net/hotspot/hotspot.html>

    Deshaker filter:
    Yes, but...
    ....I do happen to have access to service manuals for various
    older Sony D8 (1st gen) and MiniDV models (for example,
    DCR-PC1E), and they all seem to have two "angular velocity
    sensors" related to Steadyshot operation. I do not know about
    the current models, though.
     
    Jukka Aho, Oct 19, 2004
    #9
  10. Matej Artac

    Matej Artac Guest

    I see. Well, I don't really know about how this works with the newer models,
    I only talked to some people who told me about the pixel redundancy being
    used in the steadyshot as well. Neither the specs nor the manual say how it
    is implemented, of course. In any case, the angular velocity sensors alone
    couldn't trigger the wobbling when the camera is static on the tripod.

    By the way, it has just occured to me, would it make sense to turn on the
    progressive recording when filming the cine?

    Matej
     
    Matej Artac, Oct 19, 2004
    #10
  11. Matej Artac

    Jukka Aho Guest

    I have been wondering about it, but as I do not own a camcorder
    with a progressive mode, I have not yet had a chance to test it
    out in practice. In any case, it _sounds_ like a good idea: film
    is a progressive medium, so why not capture it that way, too,
    keeping it progressive throughout the process (all the way to
    the DVD, or whatever the final format will be.)

    Capturing in interlaced mode - especially when the capture
    process is not synchronized to the shutter blade in any way
    - will inevitably result in field pairs where one of the
    fields is darker than the other etc, which may make it harder
    to process if you want it progressive in the end.

    (Obviously, the progressive mode in the camcorder needs to be
    a "real" one - with full vertical resolution - and not just
    the result of discarding all odd fields and duplicating the
    even fields, or vice versa.)
     
    Jukka Aho, Oct 19, 2004
    #11
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