Question about spring wound cameras

[marc]

I have a question about the regular 8 mm cameras. I have a Bolex c 8 pocket sized camera. I was wondering, If I don't fully wind the motor will the speed still be accurate? Let's say that I want to shoot at 16 fps, and I only want to shoot a given scene for a few seconds rather than 30 seconds that a fully wound motor will give you because I don't want to keep the tension in the spring when I am not shooting, can I just crank the spring a few turns and still get the accurate frame rate? Or is the accuracy only based on a fully wound spring?

[Old Uncle Barry]

Marc.
Fully wound cameras are best but I can see where you are coming from.Due to the age of the Bolex,and my own Bolex experiences (I run two models) it will be in order to just half wind the motor,as there will be plenty of torque left in it.
I know the motors are governed and will cease to operate when the motor runs down thus giving you steady power,but I thing after forty years one should give it a little help by a half wind !!

[marc]

Wel,l the one that I have is in great shape and I can tell that it did not have a lot of previous use. The speed is accurate per the dial. And also, I timed it with just two winds (wrist half winds) and the amount of time that it ran with those two winds was consistant based on the amount of time that it ran with a fully wound motor ( 22 wrist half winds). However, I have not checked to see how much footage was passed through the gate. So, I am assuming that all will be fine. I just wanted to double check to see if there is any definitive information on this issue.

[Rob]

As Old Uncle Barry says, there is a speed governor inside the camera which ensures the speed of the camera is not affected by the extent to which the spring is wound. There is also a mechanism to stop the camera well before the spring is completely unwound. If your camera is lubricated and in good condition you shouldn't have any problems.

Rob

[svabo]

Try is if it is possibil for you. Take a bit film, don´t divided d-8 film
Mark up to exampel 66,5 cm (26,18 in) =10sec. 16 f.p.s. on the film.
Drive the film through the camera 10 seconds (16 f.p.s.) and check-up the mark on the film.

[audadvnc]

...can I just crank the spring a few turns and still get the accurate frame rate? Or is the accuracy only based on a fully wound spring?

Accuracy and spring-wound don't belong in the same sentence, especially for 40+ year old equipment. If you need to shoot sync sound speed, get a sync sound camera.

[marc]

...can I just crank the spring a few turns and still get the accurate frame rate? Or is the accuracy only based on a fully wound spring?

Accuracy and spring-wound don't belong in the same sentence, especially for 40+ year old equipment. If you need to shoot sync sound speed, get a sync sound camera.

I never mentioned sync sound and I don't need to shoot it!

[audadvnc]

Then I'd go for a Filmo 70DR in 16mm or the Bolex H8 in regular 8. On most the Filmos I've seen the governor holds speed remarkably well from full wind through the 30 second shot - it's got a mechanical stop in the drive gears which keeps the mechanism from running down when the spring has lost tension. The Bolex H16 also holds its rate fairly well, so in regular 8 the H8 should provide you with similar performance.