Super 8 in a Regular 8 camera?

[MovieStuff]

Hi, all!

Now that our transfer service is in full swing, we have had quite a few regular 8mm orders come through and one of the things I've noticed is that the image on most regular 8mm rolls goes all the way across the film from one edge to the other with sprocket holes merely appearing to be punched in the left hand side of the film without regard to the fact that there is an image there. It is, in effect, "Ultra 8mm", especially if you were to letterbox the image.

Now obviously, the sprocket holes are pretty big so the height of the frame between them is affected but what if you used super 8 film in a regular 8mm camera? The pitch between the holes is the same only the size is different. I'm not that familiar with the workings of a regular 8 camera to know if the pulldown claw is too far from the edge to work or too big. Also, of course, I know the sprockets are different and that would be a problem but could be attenuated, I think, with some engineering.

Anyone out there every tried to feed super 8 through the gate of a regular 8mm camera?

Roger

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Roger Evans
MovieStuff http://www.afterimagephoto.tv/moviestuff.html

[This message has been edited by MovieStuff (edited February 27, 2002).]

[Actor]

<LI> <BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>
The pitch between the holes is the same only the size is different.
<HR></BLOCKQUOTE>
Wrong. The pitch of Regular8 is 0.15", Super8 is 0.167"

Regular 8 film is 16 mm wide. It is run through the camera twice. On the first run a strip 8 mm wide is exposed on one side. The feed and takeup reels are then swapped and the film is run through the camera a second time exposing the other half of the film. After processing the film is sliced down the center and the two pieces spliced together. A 25' roll becomes a 50' roll. A 100' roll becomes a 200' roll.

I don't see any advantage to what you suggest. If you want super 8 roll film get a double super 8 camera. It uses 16 mm film that has super 8 perfs on each side. It is run through the camera twice, processed, sliced and spliced just like reg 8.



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[MovieStuff]

Previously, I had written:

"The pitch between the holes is the same only the size is different."

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>Originally posted by Actor:
<LI> [QUOTE]
Wrong. The pitch of Regular8 is 0.15", Super8 is 0.167"
<HR></BLOCKQUOTE>

"Pitch" and "Distance" are not the same thing.

The distance between holes (from edge edge) is different due to their different sizes but "pitch" refers to the distance from center point to center point or from leading edge to leading edge since that is what determines where the pulldown claw will land.



As illustrated here, it is clear that the pitch from the leading edges of the super 8 sprocket holes is exactly the same as the regular 8mm sprocket holes. That is the reason why dual 8mm projector can even work in the first place. If the pitch between the holes was different, then the claw would not work on both. As it stands, the only thing that has to be changed is the sprockets, if there are any, and many dual 8 projectors don't have any sprockets.

In fact, the WorkPrinters are dual 8 as is the DV8 unit. Because the pitch is the same for both R8 and S8, all I have to do is feed one format or the other and the claw will land in the appropriate place, even though the sprocket hole is bigger on one than the other.

More to the point, the oversized sprocket hole serves no purpose as it relates to the pulldown claw as no other part of the sprocket hole touches the claw. That is also why both formats will work with the same claw on dual 8mm machines. So, if it will work on projectors, it should also work for movie cameras!

Now, you will also notice that the image on the R8mm frame goes WAY out to the left edge of the frame. Not all 8mm cameras do this but for the ones that do, this sort of beckons the application of "Ultra 8mm" for widescreen usage. Again, I am not that familiar with R8mm equipment but do all of them have to be split 25ft rolls? Were there none that used a 50 foot magazine that did not have to be split?

I understand the reasoning behind suggesting double super 8, however, the placement of the sprocket holes next to the frame precludes the application of "Ultra 8mm". IF there were R8mm cameras using film that did not have to be split, it would seem like modifying them to use super 8 would be cool, since the offset sprocket holes would allow for a jumbo wide aspect ratio image in between.

Just a thought....

Roger


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Roger Evans
MovieStuff
http://www.afterimagephoto.tv/moviestuff.html

[Actor]

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>
"pitch" refers to the distance from center point to center point or from leading edge to leading edge
<HR></BLOCKQUOTE>
I'll go with that definition. Reg8 is 80 frames per foot so the pitch is 12 inches/80 frames = 0.15 inch. Super8 is 72 frames per foot; the pitch is 12 inches/72 frames = 0.16666... ad infinitum or aproximately 0.167 inch. The difference is 0.017 or less than 1/50 of an inch and so would not show up in your picture. Measure out a foot of each film and count the number of frames.




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[Actor]

Now I see what you're getting at. You want a widescreen effect by using the full width of the film and by moving the perf to the frame line instead of the frame center.

It seems to me that the solution is still DS8. There are Bolex R8 and DS8 cameras out there. Both are mods of Bolex 16mm cameras. Maybe one of the shops that do these mods could replace the S8 claw with the R8 claw. That should do the job unless they also need to widen the aperature and/or narrow the claw.


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[This message has been edited by Actor (edited February 27, 2002).]

[MovieStuff]

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>Originally posted by Actor:
[QUOTE]
The difference is 0.017 or less than 1/50 of an inch and so would not show up in your picture. Measure out a foot of each film and count the number of frames.
<HR></BLOCKQUOTE>

Yes, I understand your point but the fact is that the difference is so small that they are, for all practical purposes, the same pitch. After all, measure 20 feet of super 8 film processed by one lab and compare the number of frames in it to 20 feet processed by another lab or even the same lab at a different time. The number is almost always different because film stretch is a common occurance in super 8 but doesn't affect the pitch of the holes enough to throw off registration except in the most extreme cases. Likewise, the difference in pitch you are talking about between super 8 and regular 8mm is enough to be technically different but not enough to be functionally different or, otherwise, dual 8mm projectors would simply not work with the same claw and pulldown.

Now, what I might be wrong about is this: The pulldown claw of a super 8 projector will work on regular 8mm film but super 8 film might not work with a regular 8mm claw! Why? Because the larger hole in the regular 8mm film provides a larger "target" for the smaller super 8mm claw. Once engaged, it will always pulldown to the appropriate stopping position even if its "reach" did not put it in the correct spot just prior to pulldown. The larger 8mm sprocket hole accomodates this over-shoot. However, the regular 8mm claw might not "reach" for an appropriate position for the smaller super 8mm hole, since that sprocket hole isn't as tall as its regular 8mm cousin. In that case, the 8mm claw might find itself hitting the film just above the super 8mm sprocket hole as it searches for placement prior to the pulldown.

So, even though the pitch might be close enough to be functional for 8mm film on a super 8 projector, the super 8 sprocket hole might not be tall enough to handle the placement of the regular 8mm claw at the beginning of the pulldown phase.

Hmmmm......

I don't like being wrong but it appears I might be off on this one. Humph.

Roger

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Roger Evans
MovieStuff
http://www.afterimagephoto.tv/moviestuff.html

[#Pedro]

Roger:
The pulldown claw of a S8 projector also is able to handle reg 8 footage correctly. If not, there wouldn?t be any dual format projectors. The problem are the sprocket drives before and after the gate, which are indispensabale for high quality registration, taking any mechanical load away from the claw. In S8, they are ways off from the reg 8 perforation trail, too much at the edge of the film. So, a S8 projector with sprockets would not accept reg 8 footage.
I did not know, that the number of frames per meter is different, but it seems, that this small difference is withing the tolerances the claw can handle.

The best way to go is always a specialized projector/camera, designed for ONE gauge. F.e., the two claws of an S8 projector don?t enter into the perforations in parallel: one claw is more on the right hand, the other more on the left hand of the hole, in order to compensate a little bit the missing perforation on the other edge and to take over some of the friction of the side of the gate. The second claw is not pulling the film at all, it only becomes active in case of a destroyed perforation hole. In cameras, the shape of the claw is designed very carefully in order to achieve best possible registration with the given perforation size.

Pedro

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[MovieStuff]

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>Originally posted by #Pedro:
The problem are the sprocket drives before and after the gate, which are indispensabale for high quality registration, taking any mechanical load away from the claw.
<HR></BLOCKQUOTE>

While I recognize that the sprockets are not the same and won't work between two guages, they are not required for high quality registration, at all, if the design of the feed in relationship to the pulldown claw and pressure plate is set up correctly. The WorkPrinters use no spockets and have no loop and have perfect registration. The DV8 also uses no sprockets and it has perfect registration. Now, these two units operate at a reduced speed, and I'm sure that helps, but I know of no super 8 camera that uses sprockets other than a DS8, so obviously it can be done with no loop and no sprockets and still achieve good results.

Roger

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Roger Evans
MovieStuff
http://www.afterimagephoto.tv/moviestuff.html

[Cranium]

Doesn't it seem like the recent talk of filing the gate of a S8 camera kinda gets the same effect?

There are the Bolex H8s that take 100' spools of R8, but it still needs to be split.

I'd be interested in knowing the dimensions one COULD get out of super 8, with a filed gate, etc... I was really hot on the "double-run-16" idea, but I realised that the frame height would be shorter than S8 (by about 10%), so for the time being, one could be better off trying to squeeze every little bit out of the S8 format.


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Mikel Z

[Matt Pacini]

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>Originally posted by Cranium:
Doesn't it seem like the recent talk of filing the gate of a S8 camera kinda gets the same effect?
<HR></BLOCKQUOTE>

Almost, but the problem with Super 8 is, the sprocket hole is right in the middle left of the image, NOT at the frameline.

However, this begs the question:
How are projectors able to handle both formats?

I mean, since the sprocket holes are in different places, when we project 8mm film on a Super 8 projector, why wouldn't we be looking at two halfs of frames, with the frameline right down the middle?
Get it?
How does the prjector know this, and compensate for it?
Or does it?
I haven't actually tried, so I don't know.

Matt Pacini

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