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Can I set a Bolex H16 SB to do timed exposures ?


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#1 Matthew Bartok

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Posted 16 January 2006 - 01:46 AM

I currently have in my possesion a Bolex h-16 SB with an attachable K-203 animation motor. I am wondering if can somehow "fix" either the camera itself or the motor to simulate the effect of a timed exposure function found on most still cameras ? My main goal with this camera is to do stop motion work and therefore having the shutter remain open for extended periods of time is quite desireable considering the fact that I don't have professional lighting as well as I like to shoot with an appaeture of around 16 to 22. The most simple way to acheive this would be to unplug the motor as it is half way through its cycle and thus leaving the shutter open until I plug it in again, but the camera isn't mine and I don't particularly want to damage the camera in anyway. I am also concerened with the fact that it would be a complete guess on my part as to when the shutter would be completely open. Any suggestions would be great and very much appreciated. I am getting ancy to film something as I have ten rolls of film sitting in the fridge waiting to be used.


Thank you very much,

Matt Bartok
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#2 Sam Wells

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Posted 16 January 2006 - 01:06 PM

The red dot on the single frame shaft indicates if shutter is open (down, 6:00) or closed (12:00 noon), you can see this if you use a Bolex rewind crank and advance the film with the 8 frame shaft, you'll see the single frame shaft turn and shutter open and close.

Your method sounds a bit imprecise I think.

Perhaps there's a way to get the JK motor 180 degrees out of phase and put on continuous run. Contact him maybe. You would not have control of exposure time, but it would be longer than what your motor normally gives.

Otherwise JK, Norris, others make motors & controllers for the puropse you describe.

-Sam
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#3 Matthew Bartok

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Posted 17 January 2006 - 02:19 AM

Thanks for the info. Unfortunately to the see the red dot means that I would have to take off the motor each time which is kind of a pain. I do think that if I can some how regulate the amount of voltage going into the motor I can somehow slow it down to a reasonable exposure time. I of course don't know too much about electricity and motors and such to know how to lower the amount of volts going into it.
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#4 Mike Rizos

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Posted 18 January 2006 - 11:23 PM

Matt
The Bolex H16 has time exposure capability. Set the I/T knob to T and move the run button to P. On earlier cameras this knob is a lever. The shutter will remain open till you let go of the run button. A cable release helps.
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#5 Nick Mulder

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Posted 19 January 2006 - 01:05 AM

I do think that if I can some how regulate the amount of voltage going into the motor I can somehow slow it down to a reasonable exposure time. I of course don't know too much about electricity and motors and such to know how to lower the amount of volts going into it.


You could think also about duty cycle control and a step sequence type system for your motor other wise you will still be stuck with the shutter being closed more of the time it is open - (just like it is in normal operation) - with the right set-up and long exposures you can get effective shutter angles of 350 deg+ (using a fair amount of ND filtering) -


depending on what type of motor you have in the drive you will need to either learn PWM or stepper motor control (info all there for you on the net) -

After about 3 months of painful reading up on electronics my particular solution was to go with a servo type system (and I still know bugger-all :blink: )


(yep, I know the grip makes no sense :D )

Edited by Nick Mulder, 19 January 2006 - 01:07 AM.

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#6 Boris Belay

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Posted 19 January 2006 - 09:03 AM

Matt, I'm not sure I understand what you're getting at... you have an animation motor (with a timer ?) but no shutter timing on the motor, right ? (I'm not familiar with that JK motor, which is not on their site anymore.) So you want to trigger the motor manually (I suspect), but unplug the motor at each frame (or reduce its voltage, but I find that a very iffy solution : the motor will either not start, or be very unreliable, I imagine), in order to get the shutter time you want. That sounds very convoluted, unreliable, and frankly not the best way to start on those films you are so excited about.
The H16SB is a very good camera, so you've got a good base there. It sounds like the motor you got may not be appropriate for you purpose. Knowing JK, I'm sure it's very good too, so it would be a shame to underpower it and lose the whole point of its precise electical characteristics. I would suggest that you do yourself a favor (and spare the time and trials of getting this undervoltage thing right), and trade that motor for one that has shutter timings built in or the ability to use the variable shutter timing ('T' setting on the 'I/T' knob) in the single-frame mode of your SB.
Or else, just get more lighting... You say you don't have pro lighting : do you really need it ? How about just plain halogen lamps with some kind of diffusing or reflective material ? If you're doing animantion in a fixed place, it wouldn't be hard to set up (more difficult to build moveable lighting).
The fixed shutter timing ('I' setting on the 'I/T' knob) in single-frame mode on the SB is 1/30th of a second. Could you not work with that and rely on the camera's precise mechanics (or your motor's) ? This seems all the more important since every frame counts in animation and you need to know your set-up is right.
-B
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#7 NCSProducts

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Posted 17 March 2006 - 07:54 PM

After about 3 months of painful reading up on electronics my particular solution was to go with a servo type system (and I still know bugger-all :blink: )
(yep, I know the grip makes no sense :D )

Very similar to a TimeFlow Intervalometer!
And looks easier to handhold.
But does it do long exposures? :unsure:

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#8 Nick Mulder

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Posted 20 May 2006 - 04:04 AM

Very similar to a TimeFlow Intervalometer!
And looks easier to handhold.
But does it do long exposures? :unsure:

Posted Image
<subtle plug>
Pick up a TIV for cheap on eBay
Ends in two days!

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wowsa, older post i didn't keep up with

yep, I have complete control over on and off times, well... there is the time it takes for the servo to get from back to forward tho...

I've pulled that cct apart to use some of the components on a crystal sync cct I'm working on - + I think next I'm going to use the servo on the fader to adjust for a stepper ramping drive
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