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Geneva Wheel vs Pull-Down Claw

Felipe Locca

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Sorry if this isn't the right section of the forum for this type of question.

I've been doing some reading on the history of motion picture cameras and something got me curious about the mechanics used in them.

It seems some early film cameras used the geneva wheel mechanism for advancing the film for exposure. And a lot of projectors have used the same mechanism for decades more.

But apparently it didn't took long for camera designers to move away from the geneva wheel to use pull down claws of various forms.

I imagine there is some reason for that. First I assumed it could be that pull down claws are more precise or durable, but it seems that projectors kept being designed with geneva wheels through out the XX century. And I got the impression that projectors need the same precision and probably even more durability than cameras, as they might run for a lot more hours overall.

Considering the the geneva drive appears to be a lot easier to design, manufacture, assemble and repair, does anyone has an idea on why that happened?

The only reason I can imagine is noise, maybe the claw mechanisms are overall more silent. That would explain why the geneva drive on cameras was more common in the early days before sound for film was developed.

Also, if anyone has any recomendation of any book or text regarding the history of development of the mechanics of film cameras I'd love to learn more about that!

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I think there were a few reasons camera designers moved away from the Geneva mechanism.

Noise reduction would be one, something which was beneficial in cameras from the late 20s as sound came in, and absolutely essential with blimpless cameras from the 60s on. Projectors, by contrast are commonly situated in sound-proof booths so noise is less of a factor.

The other reason I think would be the ability of cam and multi-link movements to create custom pulldown curves with dwell periods to help stabilise the film and prevent perf damage. A Geneva movement pulls down in about 90 degrees, which is much faster than most camera movements, so the acceleration is very abrupt, and would probably damage celluloid perfs at high camera speeds. I suspect stability in film capture is more important than in projection, though someone else might have more knowledge about that aspect than I do.

There is a real dearth of literature on the history of movie camera technology. One of the few decent books is this one:


Googling dwell mechanisms is an interesting window into the technology of movie camera movements.

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I have understood the lower top speed with fragile filmtypes and the noise level are the main reasons. It MIGHT have something to do with the maintenance/lubrication too as most of the projectors have pretty OK continuous lubrication arranged with steady stream of oil supplied to the most important bearings and parts, but most cameras don't have anything like this except some models like mitchells and such which have a certain amount of oil arranged for the critical parts. Just saying that projectors are expected to have more regular fresh oil available than cameras in overall which might affect a little what type of movements are chosen for cameras as well (everyday oiled ones not ideal)

I suspect the geneva needs more space too compared to simpler movements depending on what it is compared to but not sure about that.

projectors ARE noisy indeed, often so that it is unpleasant to stand next to it for too long ... let alone trying to record dialogue near it.

projectors have different shutters than movie cameras (usually flash the same frame multiple times to reduce flicker)and thus need different pull down cycle than a movie camera (movie cameras don't use multiple exposures on the same frame. though on the viewfinder it is possible to reduce viewfinder flicker by dividing the mirror surface to sectors... but that has nothing to do with the actual shutter or the exposure of the film frames)

Edited by aapo lettinen
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First to do away with a few misbelieves,

  • a professional Geneva-drive projector is not noisy when running empty (without film), the Geneva or Maltese cross can hardly be heard clicking (which it shouldn’t, if correctly lubricated), if something’s noisy, it will be the film. If the projector is noisy by itself, it’s a shitty young product. The old machines purr nicely away. The cinema as I have known it was, in part, ruined by the absence of any further development of film advance mechanisms. Single glorious exception: IMAX 70mm. Got abandoned, too.
  • the acceleration of the film by a Geneva drive is relatively gentle, given a good match of the advance sprocket with the film’s pitch. The more teeth in contact with hole edges you have the strain better distributed.
  • the making of Geneva drives is no simple thing, these units cost a few thousands. Precision grinding is involved to tenths of thousandths of an inch.

To answer the core question: mass and weight. Take the Sept by Debrie, the successor to the Autocinephot Tartara, it has a Maltese cross made from sheet metal. It wears quickly. Oskar Messter had introduced a flywheel to the Geneva drive. That improvement yielded a much smoother function overall but added as much weight as is only acceptable with projectors.

It was soon learnt that the cross and the drive pin must be hardened and submerged in oil. The best projectors of before WWI had already oil capsules. In a cinema projector you want longevity. A silent four reeler implies 64,000 advances, a sound 90-minutes film needs 129,600 steps. Projectors used to make billions of shifts during their lives, several times more than cameras.

It was also understood that the intermittent movement should be designed as a unit separable from the camera for cleaning and maintenance. A Geneva drive does not offer itself so easily for this. The fit between drive sprocket and shaft affords almost no play, you pull the sprocket with a tool, not just like that. Furthermore a camera sees almost always fresh film stock, projectors OTOH have to swallow miles and miles of variably shrunken films full of sometimes adventurous joints. Only the rugged Geneva survived that technical hell. A camera intermittent may be damaged by one wrong splice already.

Somewhat on a sideline is the discussion about shutter angles with cameras. The Bell & Howell Standard Cinematograph camera of 1911, sold from summer 1912 on, offers 170 degrees fully open. The Leonard and Mitchell cameras the same. The ARRIFLEX had 120 degrees (60 out of 180), the CINEFLEX as well. The Eyemo has 160, the Panavision R-200, surprise, 200 degrees. The faster pulldown of a four-arms star wheel drive appeared useless because we don’t have two exposures at taking but two light parts per cycle on projection, three at lower speeds. There were film projectors on the market that flash even four times per frame, allowing to lower the frame rate to 12 ps.

High-speed intermittent cameras have multiple claw tips on both sides in order to spread the pulling force over eight or ten perforation holes. Other fast acting makes use the old beater movement which pushes into the film with large contact surfaces.

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Thanks for your answers!


To answer the core question: mass and weight.


I suspect the geneva needs more space too compared to simpler movements depending on what it is compared to but not sure about that.

Makes sense, mass and weight and size didn't occur to me! But it seems like a good reason, all the claw movements I've seem look smaller and lighter than geneva drives!


continuous lubrication arranged with steady stream of oil supplied to the most important bearings and parts


It was soon learnt that the cross and the drive pin must be hardened and submerged in oil. The best projectors of before WWI had already oil capsules.

Lubrication also seems like a strong factor. I've seem a lot of pictures of claw mechanisms that appear to need a lot less lubrication(Arri 2c comes to mind), and I can imagine the difficulty to implement stronger lubrication in the smaller package of a camera!

I also didn't consider how precisely manufactured geneva drives might need to be, didn't even imagined they would need to be hardened! That brings a lot of complexity into manufacturing!

Dan and Dom, thanks for your recommendations!




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