Idea for 2-perf that doesn't involve modifying pulldown

[Zachary Vex]

Okay, call me crazy, but I've got an Eyemo and I'd like to shoot Techniscope-style images, but none of the transfer facilities in my town (Minneapolis) have the ability to do 2-perf (except scanning, which I don't want to pay for.) So being the imaginative nutjob that I am, I've come up with a scheme which I think might work...

 

First, I have a machine shop fabricate a modified gate so that only the upper (or lower) half of the image is exposed on the film, protecting the other half from being exposed at all. The film is run through the camera from beginning to end. The camera is stopped before end of the roll and turret is moved out of the way, exposing one of the frames to the open air, where the film loader pokes a pin through the center of the exposed half-frame. This marks the film so that it isn't accidentally re-inserted in such a manner as to expose over the original shots!

 

Next, the camera is run out in the change bag and the loader flips the rolls over a-la regular 8mm, to expose the other half of the film. The film is drawn off the new supply reel until the pinhole is felt with the fingertips, which is carefully placed behind the protective part of the gate as the sprocket holes are locked onto the pull-down claws.

 

Finally, the other "half" of the film is exposed, and during the tele-cine process, the image is sized and letter-boxed to suit as the film is run through the transfer twice, once for the first half, once for the second!

 

Anyone see any flaws in my reasoning, or have any suggestions?

[Zachary Vex]

Just to be clear, I've applied for a patent on this approach. 8^)

 

I think it will help indie filmmakers make the best use of their film/process/scan money! Nothing like increasing depth-of-field and close focus while using easily-obtained spherical lenses, cutting film/process/scan costs in half, and getting all the way to 2.33 wide all at once! Imagine modifying your 35mm movie camera for about $500 with a simple screw-in gate that takes advantage of the new low-grain stocks and all of the lenses you have available in town, plus lets you use your local telecine people to take care of transfers (once forward, then again!)

 

BTW, it's called CineVex [tm]. 8^P At least that's the working title. heh.

[Nick Mulder]

how are you going to move the optical centre of the lens ?

 

especially with wides it would be noticeable ...

 

why not mask the tops and bottoms to the 2-perf aspect ?

[Zachary Vex]

how are you going to move the optical centre of the lens ?

 

especially with wides it would be noticeable ...

 

why not mask the tops and bottoms to the 2-perf aspect ?

 

good idea. i've just re-written my patent application. thanks! z

Edited December 11, 2006 by Zachary Vex

[Stephen Williams]

Hi,

 

Nothing new about that. I believe that was trick was used in India! No optical blow up either just modify the projector, not sure what happened with sound!

 

Stephen

 

Okay, call me crazy, but I've got an Eyemo and I'd like to shoot Techniscope-style images, but none of the transfer facilities in my town (Minneapolis) have the ability to do 2-perf (except scanning, which I don't want to pay for.) So being the imaginative nutjob that I am, I've come up with a scheme which I think might work...

 

First, I have a machine shop fabricate a modified gate so that only the upper (or lower) half of the image is exposed on the film, protecting the other half from being exposed at all. The film is run through the camera from beginning to end. The camera is stopped before end of the roll and turret is moved out of the way, exposing one of the frames to the open air, where the film loader pokes a pin through the center of the exposed half-frame. This marks the film so that it isn't accidentally re-inserted in such a manner as to expose over the original shots!

 

Next, the camera is run out in the change bag and the loader flips the rolls over a-la regular 8mm, to expose the other half of the film. The film is drawn off the new supply reel until the pinhole is felt with the fingertips, which is carefully placed behind the protective part of the gate as the sprocket holes are locked onto the pull-down claws.

 

Finally, the other "half" of the film is exposed, and during the tele-cine process, the image is sized and letter-boxed to suit as the film is run through the transfer twice, once for the first half, once for the second!

 

Anyone see any flaws in my reasoning, or have any suggestions?

[Nate Downes]

how do you mark so as to make sure that you don't accidentally double-expose a roll, or even worse, half-double-expose? From my math, you have a 25% chance of getting it right on re-load.

[Zachary Vex]

how do you mark so as to make sure that you don't accidentally double-expose a roll, or even worse, half-double-expose? From my math, you have a 25% chance of getting it right on re-load.

 

Repeating what I said above...

 

"The camera is stopped before end of the roll and turret is moved out of the way, exposing one of the frames to the open air, where the film loader pokes a pin through the center of the exposed half-frame. This marks the film so that it isn't accidentally re-inserted in such a manner as to expose over the original shots!"

 

"The film is drawn off the new supply reel until the pinhole is felt with the fingertips, which is carefully placed behind the protective part of the gate as the sprocket holes are locked onto the pull-down claws."

[Chris Keth]

Not a terrible idea but as Nick mentioned above, how do you move the lens when you reload to shoot the other half-frames? It will be noticeable on wider lenses and will look like moving a view camera with a rise or fall movement applied.

 

Honestly, if you want to shoot 2-perf that much and are already modifying an inexpensive camera, why don't you just modify it properly, movement and all?

[Stephen Williams]

Not a terrible idea but as Nick mentioned above, how do you move the lens when you reload to shoot the other half-frames? It will be noticeable on wider lenses and will look like moving a view camera with a rise or fall movement applied.

 

Hi,

 

I don't think they worried about that!

 

Stephen

[Chris Keth]

Hi,

 

I don't think they worried about that!

 

Stephen

 

No, view cameras don't tend to move much ( :P ) but if you have ever applied a drastic rise or fall (and even though half the frame on 35mm is small, it is large when thought of in percentage of frames) and then panned or tilted, you know it's a strange look.

[Zachary Vex]

When Nick Mulder first mentioned that problem, I immediately figured out how to solve it.

 

It's easy to change the setup to park the 2-perf window in the middle of the frame. This still leaves a 2-perf region unexposed.

 

As far as the idea of using 2-perf pulldown, there are zero transfer houses in Minneapolis that can handle that... however, they can all handle this idea, which is 4-perf pulldown but would have to be transferred twice on each piece of film, once forward and once reverse, just re-framing and re-centering in each direction. And to anyone else poo-pooing this idea, the conversion for any camera would only be in the hundreds of dollars (a new gate only) rather than the thousands required to convert to 2-perf pulldown.

 

The advantages are immediately apparent to anyone familiar with Technoscope 1:2.33... you can use spherical lenses, get full depth-of-field, pay half as much for 35mm film stock and development, convert a camera for a song, and gain 25% vertical resolution and 40% width over a Super 16mm frame. The only disadvantage over 2-perf pulldown (Technoscope) is that the film has to be marked and re-loaded carefully so as to not re-expose any frames, and the total run-time per roll is the same as standard 35mm cameras rather than double for 2-perf pulldown. Also, keep in mind that the negative cannot be conformed... it must be scanned for release prints, but that's really not a problem in 2006 if an indie company gets that far.

[Paul Bruening]

Zachery,

 

I have to admit, this is a pretty darn good idea.

[Hal Smith]

How do you know where you're at on the 2perf/4perf scheme of things if your film runs out? This would only work if you don't ever run your film out on a shot. Otherwise you might as well rewind the half exposed roll in a darkroom and start over from the marked head of the roll offset two perfs.

 

On balance though it is a heck of an idea!

[Paul Bruening]

No sweat. When you load the first time, you hand turn the works until the claw pulls out. Then, you pull the lens, take a Sharpy and run the tip around the edge of the gate then mark a "1" in the rectangle. The next time you reload the same roll, you mark the adjacent frame with a different rectangle and put a "2" inside it. You have to jimmy the film around in the sprockets sometimes but you can reliably line up the second set of frames. Of course, if you don't have your head screwed on straight when you do this, you botch up a lot of work and may not know it until the dailies come back.

 

It is a riskier system than a 2 perf pull down due to the chance of misaligning the two tracks (for lack of a better term), but darn clever on the do-it-for-cheaper scale.

[Zachary Vex]

If the film runs out you are not screwed... you simply don't expose it in the opposite direction. That one roll costs you normal 35mm film and processing instead of half.

 

I realized this morning that there's one more problem I didn't address... the fact that the perfs pull down from the bottom of the hole in one direction and the "top" of the hole in the other. That will cause the "center" of the frame to be offset when the film is flipped in the other direction... no problem, though. I can't set the gate exactly in the center vertically... it will have to be very slightly offset up or down to compensate for the perf size. Yes, this will introduce very mild distortion in the corners of the frame when shooting 1:2.33 with a very wide lens. Will anyone notice? Heck, I've suffered watching all sorts of visual distortions associated with anamorphic shooting and projection ever since I was a kid... I'm sure it won't be a problem at all.

 

BTW, for those of you worried about changing a roll in a change bag or tent, trying to feel the position of a frame that's been marked with a pinhole, there's a solution to this problem as well. This guy offers cassettes that allow you to load a camera in full daylight and then drop the film into place in the change bag once you're finished.

 

 

http://www.supervision2perf.com/

 

No sweat. When you load the first time, you hand turn the works until the claw pulls out. Then, you pull the lens, take a Sharpy and run the tip around the edge of the gate then mark a "1" in the rectangle. The next time you reload the same roll, you mark the adjacent frame with a different rectangle and put a "2" inside it...

 

Brilliant except for one thing... the frame you've marked "1" is at the original "head" of the roll. When you're ready to change direction, you're at the tail. Oh well!

[Hal Smith]

No sweat. When you load the first time, you hand turn the works until the claw pulls out. Then, you pull the lens, take a Sharpy and run the tip around the edge of the gate then mark a "1" in the rectangle.

I guess that's a given then, you have to plan to rewind rolls if one ever runs out. IMHO it would be best to implement the system planning on rewinding all your rolls. Probably on a longer shoot always re-running rolls on the next day would make for smooth operations. I wonder what experienced AC's like Doug Hart would think of this idea - I'll email him and get his opinion. Bruce at Aranda would have some interesting input also.

[Paul Bruening]

I wouldn't try to run the film in both directions for the reason you stated, Zach. The frame line in techniscope is thin to begin with. I don't think the perf holes will allow you to pull that off. I do think you can rewind the rolls and shoot them again. If you have a camera that can transport film in reverse, well, problems solved.

 

I wouldn't try to run the film in both directions for the reason you stated, Zach. The frame line in techniscope is thin to begin with. I don't think the perf holes will allow you to pull that off. I do think you can rewind the rolls and shoot them again. If you have a camera that can transport film in reverse, well, problems solved.

As well, let a shop that knows cine do the machinig. Bob and Mark at Fries or Bruce at Aranda Film Group are some that come to mind.

[Zachary Vex]

Kodak keeps their perf holes cut to a very tight spec. I'm absolutely certain that offsetting the gate very slightly up or down will make every last fraction of a millimeter available for exposure in both directions!

Edited December 11, 2006 by Zachary Vex

[Paul Bruening]

I look forward to hearing about your results. Please, keep us up to date.

[Zachary Vex]

Hey Paul, your domain is expired.

[Nathan Milford]

Zachary,

 

I believe the Crook Bros. have a prototype setup for that system or something similar.

 

Additionally they've shot tests doing 'double run' 16mm by shooting 2-perf 35mm.

 

ARRI has shot 2-perf anamorphic (with the element rotated 90 degrees) and deanamorphosed into a 4-perf 35mm image.

 

Interesting stuff...

[Nick Mulder]

good idea. i've just re-written my patent application. thanks! z

 

 

Well, I hope you include me on the patent - I'm looking forward to my %49

[Zachary Vex]

Del Olson of Delden Film Labs sent me the following warnings about this idea:

" I would worry mostly about the camera proceedure. Any mishap at that point and you would have a double exposed waste of time. You would also have watch for loosing the loop in the camera.

 

From my experience, the average assistant cameraman would have trouble with this concept. If they chew up the film while loading, that section of film has to be cut off before it is processed, because torn perfs will not make it through the processor.

 

A pin hole would be hard to feel or find, I would tape on a dot. I use tape o dots for the telecine, so the sync dot is white on a neg. They work great. You need a punch in the film instead of the tape on dot, for going through the processor. If the has a magazine that has a loop of film sticking out of it, the dot could be replaced with a 1/4" punch while reloading. Slating the scenes would have more importance since the film would be hard to identify heads from tails after processed. The little bit of film cost savings you might enjoy would most likely be burned up in extra telecine time, sorting things out.

 

You would end up cropping it down to fit 16x9. If you were thinking about film finish, a chat with a lab that does optical printing would be a good idea b-4 going forward.

 

If you are thinking about a 2K scan for film finish through video, I would just use super 16mm, which is getting to be the new medium for features going that route and save yourself a lot of agrivation.

 

I think b-4 you start on this project, you owe it to yourself to ring out the existing formats for what you want to accomplish. Something like anamorphic super 16mm would be real close to what you are talking about."

 

Sigh. I guess perhaps I got a little ahead of myself with this thing. Maybe I should just be happy I've got a super 16mm Aaton.

Edited December 11, 2006 by Zachary Vex

[Charlie Peich]

You can easily do this with a 435 or Arricam (I just tried it on a 435). Here?s what you need to do and get. All off the shelf parts from Arri:

 

Set the lens mount on the camera for Super 35. This gives you the full width of the film stock and will save you time shifting the image latter on in transfer. Arri doesn?t have a HARD MASK for 2.35 in Academy format anyway.

 

Change the Format Mask or hard mask in the gate to the Super 35 / 2.35 centric mask Arri offers. This is part number K5.59773.0 . Arri Guide. This mask has an opening of 24.9mm x 11.1mm. The height of the full frame S-35 frame is 18mm, so there will be a frame line that has an overlap of about 1mm thick consisting of the very top and very bottom of the exposed frames with this mask. I just traced this out on a piece of film. I?m sure you could get Arri to make a 8.9mm high mask if this 2-perf method was acceptable.

 

Next you?ll have to change the ground glass to Arri?s S-35 / 2.35 centric glass Arri has. This is part number K2.47416.0 . You?ll have to watch the very top and bottom of your frame because of the 1mm overlap of the frames. Again, if this method of 2 perf shooting suits you, you can always have Arri custom make a g. glass that has the proper aspect ratio.

 

Load your film and shoot away. Perhaps you would slate this ?Pass A?. As mentioned above, don?t run out at the end of the roll. When you get to the end, open the mirror and trace the outline of the 2.35 frame onto the film. Put a big x in it to help you find it after you reload the film.

 

Reload the mag. Find the frame with the ?outlined? frame you made, and line that up in the gate. Then shift it by 2 perfs either up or down. Slate this Pass B and shoot away.

 

Possible to do, but is it practical with all the risks?

 

Some of the drawbacks weather shooting a big budget shoot or your very own ?out of pocket? produced shoot:

 

Any mechanical problems that could happen on pass B could and would ruin a scene you shot on pass A and vise versa, especially if you have to open the camera door.

 

Checking the gate through the front of the camera will be the only way to check because opening the door while shooting pass B you would fog any scene previously shot on pass A, or while on pass A, you would fog the film for pass B yet to be shot. Once you loaded the film for a pass, you have to keep the door closed. Period. Also, when checking the gate with the lens off, you usually expose the film with so much light, the over exposure will ?bleed? over to the frames before and after the frame your checking, resulting in a flash on previously exposed film on pass A or a flash on the yet to be exposed scenes on pass B. This will make it harder to check the gate. Ok, I?m sure this could be fixed in post, but it will add more time to your edit.

 

This running the film through the camera twice used to be done in the old standard 8mm home movie days with 16mm wide film perforated for regular 8mm. After you rolled the film through the 1st time you would flip the roll over and run it through again to expose the other half of the film. Then the film was slit in half after processing. It worked.

 

It will take more time to reload if you take the mag off, go into the bag, reload it etc. You could shoot 2 or 3 rolls on pass A, then shoot the pass B on the 2 or 3 rolls. If you are shooting 400 ft rolls, you expose pass A, then start shooting pass B, then you finish with 150 ft left, you have to cap the lens and finder and roll off the remaining 150 ft. Remember, you can?t just open the door and unthread the mag? you?ll ruin shots on pass A.

 

I don?t think registration with these cameras would be a problem, as you would be using new perfs for pass B.

 

Would Kodak?s Key Code work on pass B? You would have to keep good logs of what you shot, and the lab would have to get the rolls prepped in the proper order to save you color correction and transfer time. I also agree with the warnings from Del Olsen.

 

Trying to modify an Eyemo would be a lot of time and $$. Most of the aperture plates for those cameras are in Academy format. Maybe you?ll find one in the ?silent? or now S-35 format. You can cut the smaller Academy format aperture to the larger S-35 easily, but what are you going to use to ?fill? in the aperture to the opening for a 2-perf aperture? When you run the film through the Eyemo the 2nd time, you would be using unblemished perfs as the Eyemo has the pull down claw on the one side. Hopefully you have a machinist who will work with you. It would be best to find someone who is familiar with cine cameras or has worked on Eyemos. These cameras look simple, but they need precise alignment when changing the gate.

 

A camera set for 2-perf pull down is the only way to go for speed in production, no worries of previously exposed scenes and economy in post. However, I?m tempted to try this on the 435 at some point.

[Jon Kukla]

It just seems that this is creating a lot of other far more bothersome and just as expensive, but even less-standardized problems in order to avoid changing the pulldown mechanism. Either way, you're still going to encounter all of the same problems in post as 2-perf, plus a few more it seems!

 

By all means go ahead with this and let us know, but frankly, I think that if you're looking for innovative ideas regarding 35mm origination, there's still a ton of abandoned formats from the past 100 years that probably are worth looking into reviving (a la Techniscope) instead of trying to start fresh. And it's worth noting that the 2-perf idea was mooted as far back as 1930, btw...

 

As stated below, the 90 degree anamorphic concept is probably the most interesting. I think someone else here suggested using that in conjunction with 1-perf to get 2.39 images while having a 44 minute mag off of 1000 feet. Now that is amazing.