8MM CINE FILM COPYING TO VIDEO

A forum to share ideas and opinions on the equipment and technical aspects of film, video and AV making.
DigitalDingbat
Posts: 1
Joined: Thu Feb 09, 2012 6:20 pm

Re: 8MM CINE FILM COPYING TO VIDEO

Post by DigitalDingbat »

Can I second the above request with a bit of a question re projectors that are able to run with 60c/s and 50c/s.
If you run the projector on the 60c/s setting when using 50c/s mains will this slow the projection speed to 15fps from 18fps?
My projector has a different set of pulleys so looks as if it would.
So when projecting an old Std 8 16fps film on an 18fps projector although this is a tad slow it might be 'better' than too fast.
tom hardwick
Posts: 914
Joined: Mon Jan 29, 2007 9:59 am

Re: 8MM CINE FILM COPYING TO VIDEO

Post by tom hardwick »

It's certainly worth experimenting with the different mains frequencies settings as all you really want to do (with machines that use a three-bladed shutter) is to project as close to 16.7fps as possible. Generally if you view the footage on a TV it's pretty easy to see if flicker is spoiling the transfer, but I do find there's a tolerance on that 16.7fps figure depending on the shutter sector angles and claw pull-down speed.

tom.
whittington
Posts: 8
Joined: Tue Jan 24, 2012 3:36 pm
Location: Worcestershire

Re: 8MM CINE FILM COPYING TO VIDEO

Post by whittington »

tom hardwick wrote:It's certainly worth experimenting with the different mains frequencies settings as all you really want to do (with machines that use a three-bladed shutter) is to project as close to 16.7fps as possible. Generally if you view the footage on a TV it's pretty easy to see if flicker is spoiling the transfer, but I do find there's a tolerance on that 16.7fps figure depending on the shutter sector angles and claw pull-down speed.

tom.
Some years ago i tried a simple light dimmer switch on my projector and this cetainly had some control on the speed. I never got round to trying to do anything with it so can't say this would be sucessful in getting the projector running at the required speed.
richardian
Posts: 7
Joined: Sun Dec 18, 2011 2:39 pm

Re: 8MM CINE FILM COPYING TO VIDEO

Post by richardian »

Hi,

In theory it's simple, taking 18fps as a starting point. You need a digital or analogue video camera set to 1/50th shutter speed. You set your 3 blade projector to 16.67 [=16&2/3rds] frames per second. Now both projector and cam are synchronised.

How does this work? Well if you times the fps by three you get the shutter speed 50.

Now I say in theory, and the theory is sound. However, in practise I have never found a projector which will hold its speed 100%. Projectors warm up, projectors slow fractionally as they take up the inertia of a new reel & so forth, all of these things can fractionally vary your speed if only by half a frame per second, and that will throw the numbers. A possible aid to arriving at a steady film speed might be to have a very long, numbered film leader strip which you could focus on and trim your speed, neutralising any flicker before you encounter the main feature - that's an untested theory btw.

Then there's luck, and then there's skill - some people have a knack of just getting it right.

Be very careful experimenting with projector currents please. There are a vast number of projectors out there and a vast variation on how their motors are set to run, some projectors will try & hold onto their pre-set speeds whatever you do to the voltage, you could ruin the projector or even receive an electric shock. To go into the 'guts' of a projector you need to know absolutely what you are doing & probably have a qualification in circuitry and electronics as well. The safest speed projector is one with a variable speed dial built into its manual control panel, there are a few of these around.

And always un-plug the projector if you are working inside it, changing a belt or for similar reasons.

Ric
User avatar
Dave Watterson
Posts: 1872
Joined: Sun Jan 28, 2007 11:11 pm
Location: Bath, England
Contact:

Re: 8MM CINE FILM COPYING TO VIDEO

Post by Dave Watterson »

I have long maintained that the only sensible way to copy cine to video is frame by frame. That avoids all those speed issues. Yes it takes time, but it does not waste time.
tom hardwick
Posts: 914
Joined: Mon Jan 29, 2007 9:59 am

Re: 8MM CINE FILM COPYING TO VIDEO

Post by tom hardwick »

I know you're right Ric and you should use 1/50th sec as your camera's shutter speed but I do resort to 1/25th sec when film I receive is very under-exposed and this is often better than upping the gain by a further 6dB. I find it's impossible to determine what shutter speed was used on replay of the timeline, and I suspect a lot of this has to do with the frame blending that is going on anyway, where 18 frames are being converted to look like 25.

I do notice that my 3 CCD camera gives better transfers than my 3 CMOS camera, as the way the latter's chips are scanned makes retrieving individual frames a lot more difficult.

Dave's right - scanning each and every frame is the way to go, but for 1200 feet? And even then you have to resort to frame-blending to get the speed right - negating a lot of the plusses individual frame scanning theoretically brings.

tom.
chrisk

Re: 8MM CINE FILM COPYING TO VIDEO

Post by chrisk »

Since the publication of a picture of my machine for cine capture in the last issue of FVM 'Southern Script', I have received several requests for more information. I have now produced a write up on the construction and operation of this equipment and the article in pdf format is available on the home page of our club's web site http://southdownsfilmmakers.org.uk/. Click on 'For the Technical Minded' if you have an interest in this method.

I have found the results using this set-up to be much better than anything I have ever achieved by projection methods. As commented, the process is slow but the whole machine can be left chuntering away for as long as necessary, even in a lighted room, and as it is one piece any movement round it does not disturb the positioning.

To add a little about introducing extra frames to bring 16 or 18 fps up to 25 video fps, I do this in Premiere. You can't see fields in Premiere so analysing the fields in After Effects shows how well this is handled. Each jpeg image from the capture process is 720 by 576 pixels and when the series of images is rendered as an avi in Premiere, each single image is converted to two interlaced fields to make up each frame. For 18 fps material the speed of the clip must be multiplied by 72.00% (18/25) and Premiere introduces extra fields (rather than whole frames) to make it up to 25 fps. This results in very smooth action. To compare this with projection methods, even if the projector speed is accurately adjusted to 16.67 fps, each cine frame results in 3 fields of video so every other video frame comprises a field of one cine frame and another field of the next cine frame, so the resulting field structure is virtually the same as adjusting the speed/duration in Premiere. In any case to accurately reproduce the 16 or 18 fps of the original cine, speed adjustment is editing is still necessary with resulting addition/subtraction of fields.

Like Dave, I agree frame by frame is the way to go, and building the equipment provided an interesting exercise.

Chris
richardian
Posts: 7
Joined: Sun Dec 18, 2011 2:39 pm

Re: 8MM CINE FILM COPYING TO VIDEO

Post by richardian »

I was wrong about projectors & I apologise. I have only just discovered that a projector I took for granted as being a 3 blader is actually a 2 blader so I have spent seven days trying to coax a 16.67fps transfer out of a shutter blade system that equates to 25fps when used with a 1/50th shutter speed capture cam. I am getting better results now and the TQIII holds its speed, as I anticipated from a sound projector. But I am still looking to refine the result.

Frame-by-frame has got to be better and I look upon it as superior flick book technology in state-of-the-art digital terms. But I like 1:1 moving frame capture, the result gives me the mechanical sensation of both a cine camera and a cine projector and that's something I perhaps rather eccentrically appreciate, but that's just me. However I am still looking for a better image resolution than I am currently achieving.

Many thanks & to all.

Ric
richardian
Posts: 7
Joined: Sun Dec 18, 2011 2:39 pm

Re: 8MM CINE FILM COPYING TO VIDEO

Post by richardian »

tom hardwick wrote:I know you're right Ric and you should use 1/50th sec as your camera's shutter speed but I do resort to 1/25th sec when film I receive is very under-exposed and this is often better than upping the gain by a further 6dB...

I do notice that my 3 CCD camera gives better transfers than my 3 CMOS camera, as the way the latter's chips are scanned makes retrieving individual frames a lot more difficult.
Hi Tom, I keep with 1/50th. On my (ageing) cam 1/25th is down as for use in subdued light conditions I think. Apparently CMOS gives you 'rolling shutter' which sounds like a nightmare, in that context 3CCD is better but more expensive to produce, so we are seeing the newer cams taking a step backwards in some aspects of image quality it seems?

Ric
Michael Slowe
Posts: 807
Joined: Mon Jan 29, 2007 4:24 pm

Re: 8MM CINE FILM COPYING TO VIDEO

Post by Michael Slowe »

Unless you chaps really enjoy messing about with shutter speeds and frame rates I repeat the advice I posted last year on this topic, ask the kind and talented Tom Hardwick to do your film transfers for you, it will save you endless trouble and, I'm sure, won't break the bank!
tom hardwick
Posts: 914
Joined: Mon Jan 29, 2007 9:59 am

Re: 8MM CINE FILM COPYING TO VIDEO

Post by tom hardwick »

CMOS chips are good for the manufacturers because size for size they're more light sensitive and at the same time they consume less power, so what's not to like? What's not to like is the flash banding that I've gone on about at length in Positive image, and likewise the jello-wobble that comes free if you pan quickly or shake your camera about.

OK then, you say - don't do either of those things. But my test of the GoPro showed that when you attach such a 'helmet cam' to your bike and do something as simple as ride across the park, you get both of those things - fast pans and vibration. Same with any extreme sport for that matter, and probably to a much greater extent.

You can take out the vibration with something like Prodad Mercalli's image stabilisation software, but that just makes the jello-wobble look even more obvious. I find it's best with the shakes left in - that way CMOS's failings are disguised behind other failings. A bit like aerosol spraying in the loo instead of opening the window.

CMOS chips are read out somewhat like a CRT display, so if you shoot helicopters, all the rotor blades appear curved. Not so with CCDs. And if you use CMOS for film transfer, often the top of the individual frame is mated to the bottom of the next frame, such that retrieving individual frames (especially across a splice) is made much more difficult. Not so with CCDs.

I like CCD cameras which is why I hang onto my FX1, but I fear we won't see them used again.

tom.
col lamb
Posts: 680
Joined: Tue Oct 16, 2007 9:51 pm
Location: Preston, Lancashire

Re: 8MM CINE FILM COPYING TO VIDEO

Post by col lamb »

A few weeks ago I thought that I would; at last, copy my old cine films onto the PC via my HD camcorder.

Dug out my old projector and tried it to see if it still worked, all seemed OK.

Spent hours cleaning every roll of cine I wanted to digitize, set up projects in CS5.5 in readiness to add sound to the old masterpieces (well they were not really but I did enjoy making them).

Set projector, screen and camorder up and commenced recording, then disaster struck and the Saturday morning burn out occured on the first roll (remember them from the Children's cinema every Saturday at the Odeon).

Despite best efforts the projector refused to drive at all, its now been recyled in accordance with the WEE Regulations.

One day I'll borrow another projector and try again.

Such is life.
Col Lamb
Preston, Lancashire.
FCPX, Edius6.02, and Premiere CS 5.5 user.
Find me on Facebook, Colin Lamb
User avatar
Dave Watterson
Posts: 1872
Joined: Sun Jan 28, 2007 11:11 pm
Location: Bath, England
Contact:

Re: 8MM CINE FILM COPYING TO VIDEO

Post by Dave Watterson »

What a shame! I feel for you.

My best "burn out" moment happened in Edinburgh's illustrious art-house cinema, The Cameo. At a suitably impressionable age I was watching Olivier's Hamlet. We reached the great duel scene at the end on a huge flight of stairs ... when the black-and-white image erupted into colour. Wow, I thought. What a trick to do the climax in colour! Then the image shrivelled and the performance stopped.

There is, of course, a lesson in Col's disaster ... make sure you do your films to video transfers before all the working cine gear gives up the ghost.

Dave
richardian
Posts: 7
Joined: Sun Dec 18, 2011 2:39 pm

Re: 8MM CINE FILM COPYING TO VIDEO

Post by richardian »

Touch wood I have not encountered 'burn out' (yet). For transfers use a low wattage bulb 15W or 25W with a sliver of white glass or perspex between the light source and the gate, then your film cannot be burnt. But in adapting the lamp house make sure the projector is unplugged.
chrisk

Re: 8MM CINE FILM COPYING TO VIDEO

Post by chrisk »

Further to my post about frame by frame capture, I have now designed and built a cine to video synchroniser that allows accurate frequency and phase synchronisation of the video camera controlling the projector at precisely 16.667 fps. With phase control, this system gets over the problem of CMOS rolling shutter as each field is captured during the open portion of the projector shutter. It works equally well with CCD camcorders. For those with an interest in these techniques, full details are given in an extension of my article available on the South Downs Film Makers web site http://southdownsfilmmakers.org.uk/

Chris Kenny
Post Reply