Re: Solenoid Cable Release

[Greg Erker <erker@xxxxxxxxxxxxxx>]

>I would like to use solenoids to trip dual cable releases on a twin
>rig.  Currently, I trip the pair of 6" cable releases by my fingers
>(sometimes using a popsicle stick). There is enough movement in the
>cables that the shutters are somewhat out of sync.  Does someone
>here know how to create one of these?  I walked into a big
>electronics supplier and described what I was after.  He replied,
>"Gimmee the part number."  :-(

  I've heard that the flex in dual cables
is enough that you can't perfectly synchronize
two cameras. Thus pushing two releases with
one solenoid will presumable have the same
problem.

  Better, I think, is two have a solenoid
for each camera. A benefit is that you can
then separate the two by 10 or 100 feet just
by adding some wire between them and the control
box.

  Try doing a web search on "surplus"
and "solenoid". I have once found a web site
that had some decent looking ones for a few
or 3 bucks each.

  Take a look at Steve Spicer's web page to
see how he fires his dual Pentax system.
http://www.werple.net.au/~kiewavly/pentax_rig.html

  I wanted to do something slightly different.
Use push type solenoids rather than pull ones.
Easier to interface to a short cable release
I think. A solenoid like the Guardian 11P-Int-6D
(push type, intermittent rated, 6VDC) might work.
Has a lift and stroke of 32 oz at 1/8" and 4.8 oz
at 3/4". Price is $18 CDN in an old Electrosonic
catalog (Canadian Electronics place). Maybe $15 US?

  From talking to Steve I think the trick is to
charge up a big capacitor to a high voltage (to overdrive
the solenoid) and then fire the cameras. If you
are also using the solenoids to perform the B (bulb)
holding you use a reduced voltage to hold them on.

  BTW if you get a good design there probably is
a market for it for hyperstereo shooting.


>I recall that they used these things for wildlife photography.
>Perhaps Contax was a brand.  There seemed to be wire, infrared, and
>radio-control types.  Radio-control might be the best for those
>wide-based hypers.  Perhaps the model airplane crowd would know -
>they would know radio-controlled solenoids and servos.

  All RC stuff uses servos. They move too slowly to
synchronize two cameras very well I'd guess.

>I checked some camera stores and catalogs.  Still available are
>remote tripping via air tubes and bulbs.  Do these work acceptably
>well as a replacement?

  Too slow to get good synchronization.

  I wonder if you could fill them with water
to get a hydrolic system (no delays due to compressing
the air). But watch out for leaks!

Greg