Pics of New Two Strip Camera 1

Nate Downes · January 21, 2007

First note, great idea.

Second note, swap around the order of the film strips. Red will be more blocked than green or blue, so it should be the one closest to the front.

Third, any kind of flutter between the cameras will be noticable instantly. Use a high-end pin registered system, like a Mitchell, and you'll compensate for it.

Using this on Super16 will improve a lot of things, but I see a lot of issues.

To guarantee the image, I'd strongly suggest merging the mechanisms together, off of the same drive shaft.

Herb Montes · January 21, 2007

How are you coupling the cameras to keep them in sync with each other?

Brian Rose · January 21, 2007

You all raise some good points. First off, with regards to compensating for light loss...the green filter loses (according to Kodak) approximately 4 stops, while the red loses 3 stops. Essentially, then, the green requires double the light. So, the beamsplitter I used is not balanced, that is, it is not 50/50 transmission/reflection. Rather, it reflects approximately 65% of the light, and transmits 35%. Essentially, double the light is reflected as transmitted. This way, both cameras use the same f-stop, since I have compensated by giving more light to the green, and taking a little away from the red. So, they should have the same depth of field. At least in theory. Once I get my footage back, I can see what balancing is necessary. And, switching the colors is a simple as changing the filter insert in each bolex. So, I'll give it a try!

With regards to registration, yes, this is a problem as well. At this point, being a grad student, I'm pretty much forced to use bolexes for my testing, as much as I would like to build a really kicking system using something with a superior registration system. In the mean time, I try to take care of the cameras, and ensure they are properly maintained. Overall, I think for what they are, and how old they are, they are quite good in terms of registration and steadiness. Same goes for Super 16. I'd love to have that extra leeway, and shoot wider, but it's just a matter of money at this point.

And, it is interesting you mention drives. That is what I'm working on next. I've got a pretty simple system worked out, one with a common axle that links both cameras. The drive shafts are connected via timing belts and miter gears to form a perfectly synchronous system. The drawback is that these cameras do not have the 1:1 shafts (again, money...donations accepted :) ), so any drive shaft needs a pretty good amoutn of torque. The other idea I've had is to get a tobin motor for each one, since they would then be crystal sync. Granted, they wouldn't be perfectly synchronized, but at least they would be synced to a common frequency.

Until then, basically, what I did was calibrate both bolexes to run at the same speed, more or less. Each can now shoot precisely the same number of frames (661 by my count). The problem then, is getting them to run at the same rate. Using old rolls of film, I just ran the cameras over and over again at a given speed, slowing one down, speeding up the other, back and forth until they both ran the same time. I've gotten them to where I can start them at the same time, on a full wind, and they will kick off at the same moment when they wind down. Pretty sweet!

Well, I hope that answers some of the questions. Thanks again for all the comments. They are a great help. And, I hope to have clips in a couple weeks!

Best,

Brian Rose

Kenny N Suleimanagich · January 21, 2007

Now you know why the 3-strip Technicolor process was a number of stops slower than the b&w stocks of the day.

You have no idea how much that explains to me, and answers SO many questions.

Thank you.

January 22, 2007

And, it is interesting you mention drives. That is what I'm working on next. I've got a pretty simple system worked out, one with a common axle that links both cameras. The drive shafts are connected via timing belts and miter gears to form a perfectly synchronous system. The drawback is that these cameras do not have the 1:1 shafts (again, money...donations accepted :) ), so any drive shaft needs a pretty good amoutn of torque. The other idea I've had is to get a tobin motor for each one, since they would then be crystal sync. Granted, they wouldn't be perfectly synchronized, but at least they would be synced to a common frequency.

Two different motors would have two different frequencies. And of course they would accelerate and decelerate differently (at least the older phase-locked-loop type motors).

The first application of the Revolution Motor for the Bolex was one control box driving two cameras in perfect frame sync. For a 3D filming application.

Each shutter in perfect sync with the other. As perfect as a mechanical linkage would be.

Obligatory motor plug

If you want a custom setup like that--well, it would cost less then two PLL motors.

And you get all the sync speeds from 1-48fps, plus the oddball video speeds, plus time-lapse! :rolleyes:

Brian Rose · January 22, 2007

Thanks for the suggestions. Check your pm.

Best,

Brian Rose

Bernhard Zitz · January 22, 2007

if you put a minus diopter (like certain wide-angle-adapters, for example the Schneider UWL) in front of your singlelens-system you should be able to compensate this marco effect... -9.5 dioptries should be enough...

sorry I was too optimistic :) , I tried on my bolex, you only get approx. 1.5cm (0.6 inch) of extra space... I guess that's not enough for a bulky triple-prisme...

cheers, Bernhard

Cohen Phillips · January 23, 2007

Brian it looks like you got a really neat setup! I wish you all the best of luck with it and like others I'll be waiting to see the results. I wish I lived closer to you so I could help you out with the filming of those tests! ;)

Hey...I'll tell you what...can I have first dibs on this when you move onto your 3-strip setup? LOL :D

Keep up the good work buddy.

Herb Montes · January 24, 2007

This web page shows how two Bolexes are coupled together for 3D stereo filmmaking. Timing belts and pulleys are used. Something similar can be used for your setup.

http://www.sci.fi/~animato/3d/3d2.html

This way you can use a single motor drive.

Brian Rose · January 24, 2007

Funny you should mention that. I've been in touch with the designer, asking about how he built his set up. I've bought the parts already, and my next step is to build the drive system. I made a few mods, but it is very similar to his design. But thanks for the info!

Best,

Brian R.

marc barbé · January 26, 2007

Funny you should mention that. I've been in touch with the designer, asking about how he built his set up. I've bought the parts already, and my next step is to build the drive system. I made a few mods, but it is very similar to his design. But thanks for the info!
Best,

Brian R.

Hi Brian,

I'm very touched by your search. I've recently shot three b&w negs from kodachrome, then reshot them whith red green and blue filters. The result is wonderful in depth and color fluctuations, closer to some strange 3D painting than to special effects.

Good luck on the next steps,

Marc.