Old film --> digital video --> iMovie-- MacDV Digest #2527

[Ted Langdell]

> From: "Macintosh Digital Video List" <MacDV at lists.themacintoshguy.com>
> Date: Sun, 11 Jan 2004 05:38:34 -0800
> To: "Macintosh Digital Video List" <MacDV at lists.themacintoshguy.com>
> Subject: MacDV Digest #2527
> 
> ------------------------------
> 
> Date: Sat, 10 Jan 2004 22:50:28 -0500
> From: James Asherman <jimash at optonline.net>
> Subject: [MacDV] Re: Old film --> digital video --> iMovie
> Message-id: <4BB7D894-43E9-11D8-93B8-0003933EDC98 at optonline.net>
> 
> 
> On Saturday, January 10, 2004, at 09:22  PM, Ron Siewert wrote:
> 
>> Any secrets I could try?
> 
> reduce the frame rate on your camera to 15 per second.
> J


J... Did you mean to say "shutter speed" instead of "frame rate?"

You CAN slow down the shutter speed, but on all but a few cameras like the
Panasonic models that shoot at 24 frames and 30 frames/60 fields, you can't
change the FRAME rate.

Ron:  

Try changing the shutter speed and see what happens.  You can evaluate the
results for yourself.

I think you'll find that you're not going to be able to overcome being at
odds with the mutually exclusive terms "flicker-free" and "cost effective."

8mm silent film from the time period you listed in an earlier post is shot
and projected at a nominal rate of 16 frames per second. It's usually
projected by a projector with a two-bladed or three-bladed shutter. That
flashes a single frame on the screen twice or three times a second.

The multiple showings helps reduce any perceived flicker by your eyeball,
since the image persists in the retina, and you "see" an image 32 or 48
times a second.  (48 if the film is projected at 24 frames a second with a
two-bladed shutter.)

Slowing the video camera's shutter speed down might mimic the eyeball's
"persistence of vision" (which makes viewing movies and TV possible), but
you'll still have trouble synchronizing the FRAME rate of the projector to
the frame rate of the video camera. (29.97 for NTSC video)

For 24 frame per second film, broadcast projector-camera systems use a
five-bladed shutter to help produce the "3:2 pulldown" that interleaves
multiple film frames into multiple video fields.

They also use the video signal's sync pulse to control the speed of the
projector's motor, and that allows the projector's shutter blade and the
pull-down mechanism to be adjusted ("phased" is the term) in relation to the
video frame timing so that the shutter doesn't close in the middle of a
video frame and put a shutter bar on the screen.

Phasing is similar to rotating the distributor on a car motor to adjust the
timing of the spark plug sparks... for proper firing in relation to the
stroke of the pistons.

Hope this is of help.

Ted