Synchronising leaf shutters in home-made MF stereo camera?
I need a little tinkering project this winter and I'm thinking about building a 6x6 stereo camera. The idea isn't too well thought out yet but I'm going to find a pair, or triplet, of identical MF folders that are otherwise trashed but with the lenses and shutters still good. It'll likely use an accessory rangefinder with a distance scale on the lenses for focusing, though I may go the third lens TLR (Triple Lens Reflex ) route if I'm feeling ambitious. My trouble is, how would I get two leaf shutters to fire simultaneously? (Disregarding the one behind the grassy knoll.) Are there cable releases to be found which operate two pins with a single plunger? If not, this could get really complicated, really quickly.
An LF stereo camera would be even more straight forward to build without having to worry about film winding and the holders being made to keep film flat, but the cost of 4x5 slide film would make it impractical for regular use.
There are such cable releases, for example, Nikon made one for use with a bellows which would fire the camera and stop the lens down at the same time.
I don't know if generic ones are available, I believe that particular Nikon cable release had an end that is specific to the Nikon F shutter release which doesn't have the normal tapered hole.
It would probably be far easier, not to mention cheaper, to buy two identical releases, and fasten them together somehow.
For pictures of things that do not move, a time lag between the two shots wouldn't matter much, FWIW.
Mamiya has a similar release and again it was for the bellows on the 645 cameras, they might have also had a similar device for the RB or RZ.
Hmm offhand I don't think you can get two leafs to fire simultaneously with a dual cable release. I doubt the timing will be anywhere near that precise, and you probably couldn't even use a tunable delay to synch them because the cable probably won't give repeatable results. What you need is electronic control, not mechanical. E.g. you could use the x-synch output from one lens to trigger the other, or just send one timing pulse to both. But even in this case, I have doubts that the leafs will synch perfectly unless the shutters are in tiptop condition.
How about using a focal plane shutter system e.g. a speed graphic. That'd be simple enough. You can put a rollfilm back on that, no problem. I don't know offhand if the planarity would be good enough but maybe.
Mind you, if you don't need speeds faster than 1/25 or so, you could just use a packard shutter. But then again, for speeds that slow, a dual release might be good enough. In 10 mins with a piece of tape and some plastic you could make yourself a plunger to fire 'em both. Probably good enough for longish exposures.
P.S. I have the rb/rz dual releases and they won't work for your application: the two cables are not designed to be synched together; rather, one always goes first.
Last edited by keithwms; 10-26-2008 at 10:08 AM. Click to view previous post history.
have you thought about having a bar depress
both shutter releases at the same time.
the sputnik does this ( and others as well )
here is an image of one of these bars
on an ernoflex, but it is used for focusing, rather than shutter release
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Canon made a double cable release for the FD Macro Bellows FN where you could adjust the throw on one side, which would improve the synchability. In its original application, one cable stopped down the lens, and one fired the shutter, and you could adjust it to be sure there was enough throw for the diaphragm to be stopped down before the shutter opened.
It must be possible, since there were stereo cameras before there were electronic shutters.
If you wanted flash sync, you would use a long shutter speed and sync to the shutter that fires second.
John, I like that idea of using the bar! There's also the option of just getting a Sputnik, but I've heard they leak like a Holga and besides, that would take away half the fun!
Thanks a bunch for the input everyone!
Most of the dual releases were adjustable as David says. They're not always cheap or easy to find though.
You don't need to use synch on both shutters only on one.
I agree, but luckily I remembered that KEH happens to have an FD one in stock. They have had it for a very very very long time. http://www.keh.com/OnLineStore/Produ...BCL=&GBC=&GCC=
Originally Posted by John Koehrer
$35 seems high, but maybe not.
You could also just buy an FD bellows with release, which they also have in stock. Not very sensible if you don't shoot FD, however.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."
- Rob Tyner (1944 - 1991)
if you cross-connect the 2 cocking arms with a linkage bar, they will synch and time to the slower shutter. You may have to rotate the shutters 90% to line-up so it can be done. If you wish to play with the inner workings, you can leave shutter #2 tripped so you would only need 1 cable release.
have fun with it