Electric cable release

[Bob Salomon]

Thanks for all of the responses! Bob, I would be interested in seeing an image of the system you mentioned, mainly because I'm curious about these things.

Dave, good point about vibration, it would work best as an off camera unit with a standard release cable, actually.

I am starting to do large format work in a small studio and often I am the only person available, which means that often I need to be just off camera manipulating something or other. Moving light heads, pouring a liquid, etc.

I also use a digital SLR and an RZ67, both of which can be electronically triggered and both of which I trigger using PocketWizards and my Sekonic light meter. Being able to press the button on my light meter to trigger my cameras and subsequently my strobes has become important to my method at this point.

Enter the Copal shutters and my system is killed by the mechanical releases.

So, I guess I am embarking on a small DIY engineering project and will have to build my own shutter actuator unit.

There are some important design considerations:
A) it must be fairly compact
B) it must be battery powered
C) it should be switched (triggered) via a 1/8" phono jack
D) it must be internally and mechanically dampened so that the stroke of the actuation cable is long, light, and very easy to brake - I do not want to hammer my nice shutters with the raw striker energy of the solenoid, and I want it to withstand a fair amount of cable variability (looping, routing, etc.)
E) it must be enclosed, robust, and professional looking
F) might as well throw in a small piezo buzzer to signal "open shutter" or trigger condition.
G) it should handle continuous duty for bulb mode actuation.

This type of device would also be useful with a sequencer to control the shutter during complex event sequences under software control in the future. This type of device would NOT be useful for timing critical shutter control under one second - but this is not a problem for me, I just want my PocketWizards to fire my capture and lighting sequences on these shutters like I am doing with my other cameras.

Let me just go ahead and stop you before you mention any of the commercial electronic shutters: no, I cannot even pretend to afford a commercial electronic shutter, yes I lust over them, yes I agree that they are swell!

If you can afford it you could get all of your lenses mounted in Rollei 0 and 1 shutters and then you would have fully electronic shutters with the capability for electronic or IR release on a view camera.

[aphexafx]

If you can afford it you could get all of your lenses mounted in Rollei 0 and 1 shutters and then you would have fully electronic shutters with the capability for electronic or IR release on a view camera.

Thanks for the pic of the Linhof release, Bob. To outfit my lenses with the Rollei size 1 shutters and the control unit would run me roughly $6500 - that is not even an option lol. But I dream of the day...

[Bob Salomon]

Thanks for the pic of the Linhof release, Bob. To outfit my lenses with the Rollei size 1 shutters and the control unit would run me roughly $6500 - that is not even an option lol. But I dream of the day...

If you can find them there are also Horseman ISS shutters. These are Copal shutters equipped with stepper motors. They are less then the Rollei and more then the Copal. Also larger then the Copal. The ISS 2 is quite versatile.

They are also made in 0, 1 and 3 sizes where most of the current electronic shutters are only in 0 and 1 sizes.

[aphexafx]

And a spring would also be needed on the other side of the lever to return the cable position to zero. Since both springs act in unison it may not be too hard to balance the tension of the springs to make a smooth action. A good hardware store has lots of small springs in various strength and lenths. I would play around with the setup on a piece of plywood using wood screws and once things were right I would tranfer the mechanism design to aluminum or a piece of cutting board using SS machine screws. Put it all in an enclosure.

I have some 12V solenoids here that I'm not using but they are too powerful otherwise I'd send a couple to you. A solenoid that runs off a cheap, easily swapped out, and easily charged battery system seems desireable.

Dave, this is exactly what I'm thinking, man. Great ideas, thanks for taking the time to post them!

I think that a small lever system will accommodate both a buffering spring system and allow for the transfer of the powerful but short strike of a 12v solenoid to a less powerful but longer strike needed to drive a release cable pin. As you said, any excess energy present when the release pin stops can be absorbed by a spring driving the lever itself. And, a return spring will be used to return the mechanism to the retracted state once the solenoid releases. I think this is just perfect. Also, given the shorter strike of the solenoid, the whole thing should be rather fast acting as a side effect.

I am spec’ing out parts presently (have Mouser, Digi-Key, and All Electronics catalogs open in my browser right now lol). Looks like there are some fairly powerful 12v solenoids with nearly .4" of striker travel that I think are going to work pretty well. I intend to run the unit via one 9v battery, and the charts on these solenoids are showing that I should get fairly adequate performance at that voltage.

Even better, I managed to find some black ABS project boxes that have a built-in 9v battery compartment! I'm thrilled about this.

I think a great feature would be the ability to adjust the length of the release cable sheath buy, say, 1/4" using a threaded connector of some sort in order to adjust for bending, etc. In fact, this could be put in-line up near the shutter end where you could see the tip of the cable and adjust after everything was routed around your camera. This would drastically reduce the reliance on a long strike and make the entire thing more versatile at the same time. Hmmm....

I am still slightly concerned about vibration, but we’ll see how that turns out. If the solenoid solution ends up being too jumpy, another (slower) option would be a small servo motor. But I don’t want to think about that, my money is on the solenoid…

As for mounting I already have a plan to install a 1/4" threaded bolt which I can screw into a PocketWizard and mount them both directly to my Justin spring clamp. A short jumper would then connect the two, and a nice cable release and x-sync pair would run up to the shutters on my camera. Otherwise, yeah, Velcro.

[aphexafx]

If you can find them there are also Horseman ISS shutters. These are Copal shutters equipped with stepper motors. They are less then the Rollei and more then the Copal. Also larger then the Copal. The ISS 2 is quite versatile.

They are also made in 0, 1 and 3 sizes where most of the current electronic shutters are only in 0 and 1 sizes.

I really like the ISS system - but I have been unable to find much technical information about it. You don't happen to know where to download a PDF product brochure on this system do you?

Is the stepper used to set the mechanism, which is then spring released, or is the stepper fully integrated into the shutter movement? Is timing controlled by the stepper electronically, etc.? Is the aperture controlled electronically?

Edit/Added: I found this: http://www.komamura.co.jp/e/digital/ISSG3.html - it is a sweet system, indeed. Apparently it is "opto-mechatronic", and I have no idea what the hell that implies! Does that mean my DIY thingy will be "mechano-magnetomatic"??? hehe

[Bob Salomon]

I really like the ISS system - but I have been unable to find much technical information about it. You don't happen to know where to download a PDF product brochure on this system do you?

Is the stepper used to set the mechanism, which is then spring released, or is the stepper fully integrated into the shutter movement? Is timing controlled by the stepper electronically, etc.? Is the aperture controlled electronically?

Best is to ask Horseman Japan

[Ernest Purdum]

I have noted that designers of equipment of this nature tend to use rotary rather than linear solenoids. This might be due to the stroke consideration that you mentioned.

To anybody starting out on something like this www.mcmaster.com can be a major asset in finding parts and materials required.

[aphexafx]

Great link, Ernest - and suggestion regarding rotary solenoids noted.

In case anyone is interested here are some additional links for electronic and electromechanical parts:

http://www.mouser.com/
http://www.digikey.com/
http://www.grainger.com/

[aphexafx]

Great Hammond enclosure! http://hammondmfg.com/pdf/1553D_BAT.pdf
Good looking solenoid. http://www.jameco.com/Jameco/Products/ProdDS/142464.pdf

[Photo Dave]

Something like this? I also searched for an automated timer/shutter release to do photos like this because I wanted to also get a good nights sleep and not have to baby sit the camera. When I couldn't find anything I decided to build my own. It's really quite simple, the only "high tech" component is a miniature linear actuator which drives the cable release. Very smooth, very powerful, somewhat expensive. It came with it's own controller board which I switch input voltages for on/off (in/out). A Radio Shack rechargeable battery pack and as you can see a Very modified timer from Timex. Works great... but I wouldn't try taking it through airport security!

Dave