Telecine camera shutter at 1/75th

Discussion in 'Professional Video Production' started by Joseph Brown, Sep 1, 2003.

  1. Joseph Brown

    Joseph Brown Guest

    I have a regular 3-blade 16mm Bell & Howell 2592 projector and a Canon GL2
    3CCD video camera.

    Today while I was experimenting with projecting faded film and playing with
    the camera settings to see if I can at least correct a bit for color shift,
    I discovered something totally new to me:

    With a regular 3-blade projector and the camera shutter speed set at 1/75th
    of a second, THERE'S NO FLICKER AT ALL! A 24fps records syncs perfectly
    with 29.97 fps NTSC!

    Now, what are the advantages/disadvantages to telecine film with 3-balde
    projector and camera shutter at 1/75th Vs. the "usual" 5-blade telecine
    projector and 1/60th shutter?
    Is it a better 3:2 pulldown? To my eyes, on video it looked as good as a
    5-blade telecine!
    Joseph Brown, Sep 1, 2003
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  2. Joseph Brown

    David Mullen Guest

    Now, what are the advantages/disadvantages to telecine film with 3-balde
    Modern telecines don't use a mechanical shutter to create pulldown. You're
    talking about an old "film chain" device, basically a projector pointed at a
    video camera.

    David Mullen
    David Mullen, Sep 2, 2003
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  3. Joseph Brown

    Joseph Brown Guest

    I don't think you understood my question. I never said that I'm using a
    telecine nor film chain nor a flying spot scanner. I'm using a *regular*
    3-blade projector (_not 5-blade_). With the camera pointed into a
    multiplexer and with the camera's shutter speed set at 1/75th there's no
    flicket at all. Again, with using a regular projector.

    I also discovered that my Canon GL2 has a "clear scan" feature which allows
    it's shutter to be adjusted between 60.5 Hz and 201.5 Hz.

    Mathematically, does anybody knows what would be the ideal shutter speed
    (between 60.5 and 201.5 Hz) to "telecine" a 16mm 24fps film using a
    *REGULAR* 3-blade projector?

    I don't see why should I buy a 5-blade film chain, if the camera can
    syncronize with my existing projector.
    Joseph Brown, Sep 2, 2003
  4. Joseph Brown

    David Mullen Guest

    I don't see why should I buy a 5-blade film chain, if the camera can
    You SHOULDN'T buy a 5-bladed film chain. 5-bladed or 3-bladed, the quality
    of such a transfer is only adequate for people who want to dump their old
    Super-8 home movies to video and don't give a s--- about picture quality.
    Film chains were obsoleted by telecines twenty years ago!

    If you're serious about transferring 16mm footage to video at a decent
    quality level, use a professional telecine house with a Rank or Spirit, etc.
    You're splitting hairs here, talking about 5-bladed versus 3-bladed 16mm
    projectors, between one poor transfer technique and another
    slightly-less-poor transfer technique. If you're willing to live with the
    quality of a film chain transfer, then does it really matter which approach
    is better when neither is professional quality anyway? You've already
    suggested that you've gotten results you like with your 3-bladed shutter
    projector and your Canon, so why do you even want to know about a
    five-bladed shutter projector?

    As for the optimum shutter speed, you adjust your clean scan frequency until
    you reduce the flicker as much as possible.

    What's the point of these questions anyway? Do you have some old 16mm
    prints that you need to dump onto video at no cost and quality is not

    David Mullen
    David Mullen, Sep 2, 2003
  5. Joseph Brown

    Joseph Brown Guest

    What's the point of these questions anyway? Do you have some old 16mm
    David, Ideally I would like to use a Rank Flying Spot scanner, or better: a
    Spirit Datacine Linear CCD Telecine with a DaVinci color corrector to
    transfer my 16mm reels to D5 or HDCAM.

    BUT, I have some 30,000 ft worth of 16mm reels. Bying a HUMMER truck will
    be cheaper. Besides all this, I won't make a penny out of these films.
    They are news reels form the early to mid 70's. Most of them in Back and
    White on Kodak Ektachrome 7242 film. I currenly have a community ethnic
    show on TV and sometimes I will use "archive" footage when the discussion
    calls it.

    Give it a choice between not showing any footage at all OR show a "film
    chain" footage, I'll pick the later.

    I know exacly how a Spirit Datacine quality looks like because I've done
    one. A public domain Eastman 16mm film totally faded to magenta came out
    amazing. For 22 minutes I paid $900.00 It was scene to scene DaVinci color
    correction and digital out into DigiBeta recording. The price I paid it was
    justified beause I sold many DVD's out of it.

    Back to my "personal" 16mm film reels: Paying $70,000+ to telecine archive
    material that I "may or may not" use, I will call it madness. Even a 1-light
    telecine will cost me $30,000+. Film chain is more appropriate. I think you
    agree with me. My other option is to trash the 16mm films.

    NOW, my question revolves around Film Chain. I want to get maximum results
    that film chain has to offer. MATHEMATICALLY, at what clear scan frequency
    the camera must be set in order to "match" the projector's 3-blade shutter?
    Going by eye, is not good enough as many clear scan frequencies are visually
    good. Going by eye, is an approximate good estimate. I'm looking for a peak
    value, or any formula to compute it.


    Joseph Brown, Sep 2, 2003
  6. Joseph Brown

    Bob Morein Guest

    Leave engineering to the big boys, jerk.

    And buy yourself a calculator and figger it out yerself.

    A kind soul here forwarded to me this article about the sick and
    twisted Robert Morein. It unfortunately validates all that we have
    come to know about this hopeless lunatic after a Philadelphia Inquirer
    The Supremes have already rejected this appeal, btw.
    An "inventive genius" that has never invented anything. And hardly
    "pleasantly" eccentric.
    Because no one gives a shit about a 50 year old loser.
    Not to mention the 12 years it took him to get thru high school!
    A contention rejected by three courts. From a 50 YEAR OLD that has
    done NOTHING PRODUCTIVE with his life.
    An idea that was worth nothing, because it didn't work. Just like
    Robert Morein, who has never worked a day in his life.
    Funnily enough, Drexel AGREED to reinstate Morein, who rejected the
    offer because he knew he was and IS a failed loser. Spending daddy's
    money to cover up his lack of productivity.
    Daddy throws more money down the crapper.
    It's called HIGHER EDUCATION, honey. The students aren't in charge,

    No shit sherlock.
    My estimation theory? There is NO brain at work inside the head of
    Robert Morein, only sawdust.
    Because it was bogus. Even Kalata was mortified that he was a victim
    of this SCAMSTER, Robert Morein.
    The staff at Drexel laughed wildly at the ignorance of Robert Morein.
    So Morein fucks up his first couple years, gets new faculty advisers
    (a TEAM), and then fucks up again! Brilliant!
    Morein makes LOTS of claims that are nonsense. One look thru the
    usenet proves it.
    So much for political machine judges.
    Just like all the failed "causes" Morein pursues. Heck, he's been
    chasing another "Brian McCarty" for years and yet has ZERO impact on

    Failure. Look it up in Websters. You'll see a picture of Robert
    Morein. The poster boy for SCAMMING LOSERS.
    Who better to tell us about "artificial intelligence".

    Doomed to another miserable 10 years or so as a failed member of what
    is mostly a productive human race. Most of us have successes and
    failures, but the tough get up and succeed again. And again. And

    But a twisted few are forever failures.

    Thanks for the kind summary of Robert Morein's failed existence from
    the Philadelphia Inquirer.

    A Real Brian McCarty
    Bob Morein, Sep 2, 2003
  7. Joseph Brown

    Bob Morein Guest

    Sorry guys, the above is a forgery by Brian L. McCarty.
    He's broke and bitter.
    Bob Morein, Sep 2, 2003
  8. Joseph Brown

    Bob Morein Guest

    Curious -- is the 75 fps a digitally selected value, or is it a variable
    which is continuously set?
    If the actual value were 72 fps, there would be some visible logic...
    Bob Morein, Sep 2, 2003
  9. Joseph Brown

    David Mullen Guest

    Now, what are the advantages/disadvantages to telecine film with 3-balde
    You have to understand that there is no true "pulldown" with this
    approach -- you're basically letting the movie play out at 24 fps with
    enough flashes to reduce flicker and refilming it "live" at 60i. There is
    no 3:2 pulldown employed except what accidentally might occur (for example,
    between one field captured and the next, the projector might be updating to
    the next film frame.) I'm guessing that with a 5-bladed shutter, you get 5
    flashes per frame, or 120 flashes per second, with 5 dark intervals (again,
    120 times a second.) So in 1/60th of a second, your video camera would
    receive 2 flashes and 2 dark intervals before the next field capture. With
    a 3-bladed shutter, that's 3 flashes per frame, 72 flashes per second, with
    72 dark intervals inbetween. So maybe 72 hz on your clear scan???

    But this might be assuming your projector is running 24 fps exactly and your
    three shutter blades total 180 degrees together. This is why I think you
    have to do the clear scan by eye.

    David Mullen
    David Mullen, Sep 2, 2003
  10. Joseph Brown

    Joseph Brown Guest

    He broke on what? On overdose? Asking at what settings a machine should be
    set at is not an engineering question. Asking how to design one is. This
    guy is high on drugs. So high that he hasn't FIGURE it out how to write
    basic english. Go FIGURE....
    Joseph Brown, Sep 2, 2003
  11. Joseph Brown

    Joseph Brown Guest

    This is why I think you have to do the clear scan by eye.

    I tried 72 Hz on the clear scan and I got extremely minor flickering. 1/75th
    on the sutter is better.

    What somebody suggested is to hook up a waveform monitor. Any bending on the
    waveform suggests flickering. I'll go the waveform way to determine the
    clear scan frequency.
    Joseph Brown, Sep 3, 2003
  12. Joseph Brown

    Joseph Brown Guest

    Curious -- is the 75 fps a digitally selected value, or is it a variable
    It's not 75 FPS, its 1/75th of a second. Actually, the camera is set to
    record at 29.97 fps at a shutter of 1/75th of a second. The 16mm projector
    runs at 24fps.

    The Canon GL2 allows you to choose between 12 different shutter speeds
    ranging from 1/8th and 1/15,000th of a second.
    Joseph Brown, Sep 4, 2003
  13. Joseph Brown

    Bob Morein Guest

    MAYBE there is something nonstandard about the gearing in the projector.

    If you have access to an oscilloscope and a frequency counter, you could
    compare the camera against an actual 24/72 fps source.

    Set the oscilloscope trace on "auto", and connect the sweep output to a
    frequency counter.
    Using the sweep speed vernier adjustment set to 72 fps.

    When you see the oscilloscope trace through the viewfinder as a single
    unbroken line, you have sync at that frequency.
    Bob Morein, Sep 4, 2003
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