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buggz
2-Mar-2012, 11:03
Hello,
I am guessing I need to purchase a Sinar Copal shutter to use all these barrel lens I am seeming to "collect" ?
I have a 4x5 Sinar f2 kit, I don't have the metering back.
My question to people who have and have used a Sinar Copal shutter:
Do you really NEED to have ALL the cables in order to use it?

Scott Walker
2-Mar-2012, 11:07
Just the one to trigger the shutter

rdenney
2-Mar-2012, 11:08
No. The only essential cable is the release cable, which is very expensive to obtain otherwise, and without which you cannot actuate the shutter. There is no known substitute.

But the cable that connects the shutter to the back to allow the film-holder interlock is optional. That interlock closes the shutter when a film holder is inserted to prevent accidental exposure. I've lived without that for every other lens I use, so I suppose I'll remember to close the shutter after focusing when using the Auto-Aperture shutter. The shutter will work just fine without that interlock.

Rick "who experimented with it precisely once" Denney

domaz
2-Mar-2012, 15:55
Actually there is one known substitute for the long release Sinar shutter. A bamboo skewer. It works for testing and isn't going to damage anything, wood is softer than metal. It's impossible to trigger the shutter without vibration this way though.

I have also experimented with making my own long-throw cable release out of bicycle cable housing. Basically you push the end of a standard cable release on the cable housing. Thread the cable housing with the cable release end into the shutter. Put the brake cable through the housing and push it really hard to trigger the shutter. It does work and has a little better vibration reducing characteristics but still not great.

rdenney
2-Mar-2012, 20:59
A bicycle brake cable is too flexible. It is designed to apply force in tension only.

I would suggest a different sort of Bowden cable that uses a solid inner wire designed to push as well as pull. Some control cables for automotive air-conditioners for really old cars (before digital AC controls), or the throttle cable on a lawn mower, might be something to explore. These are stiffer, of course, but if it's long enough you can still bend it around 90 degrees and eliminate transmitting movement to the camera from your hand.

McMaster-Carr sells a few models that might provide raw materials for making something. Search on "push-pull control cables".

The solid wire might be brazed or crimped in a tube to make a pushrod, but the tricky bit will be the threaded connection into the camera.

The travel is substantial--it takes quite a range of motion to cock the large shutter.

Rick "who has saved a lot of projects finding stuff at McMaster-Carr, but they're not cheap" Denney

erie patsellis
2-Mar-2012, 22:21
Rick, last time mine acted up, I measured the threads and they are standard metric threads, I'd have to remeasure to be sure, but as I recall, a standard coarse thread metric bolt threaded right in easily.

Leonard Robertson
3-Mar-2012, 10:58
I measured the travel of my Sinar cable, and it is approximately 38mm. It takes nearly all this travel to trip the shutter, most of it seems to be in the cocking of the shutter. You push and push and finally the shutter fires. I thought I would post the length if someone without a cable wished to poke something in the hole to test their shutter. The threaded end looks to be a straight thread, not tapered, so there well may be a standard metric thread die available to cut the thread onto a short piece of thick wall tubing. Then attach some sort of stout control cable to that tubing. It takes considerably more effort to fire the Sinar than a normal Copal shutter. Most of the effort is in doing the cocking.

Len

Steven Tribe
4-Mar-2012, 06:43
The time has come for me, at least, to make an alternative copal/sinar shutter release! I still have the original items, but they are not very suitable for use on travel cameras with bellows/sinar shutter/front standard/lens board/ barrel lenses combinations. Problems are:

A very long cable which doesn't like to be bent or coiled - it always "jumps" out of hand baggage when passing through security at airports.
It is far longer than necessary for my use when I am always at the side of the camera.
My field camera modification has the sinar entry hole well inside the edge of bellows. This means the kink/bend in the cable makes the engagment of the threaded end and screwing in a difficult process.

So I am going to make something completely straight and rigid, about 6" long with a little extra throw - say 4.5cm. I measure the throw on the original to be about 4.3cm. And it will be something I can afford to loose out in the wilds.

Ken Lee
4-Mar-2012, 08:27
If you can make one, perhaps you should 10 or more. If the price were reasonable, you'd easily sell them to people who would appreciate having a spare.

Steven Tribe
4-Mar-2012, 09:16
Long ago, I suggested that someone in Asia, whilst wages are still low, should get into making a (not in conflict with any registered design/patent) replacement for the long throw Sinar/Copal release (and perhaps for the Prontor Professional Shutter as well). Nothing has happened. I have some ideas about materials but the end caps on the hollow barrel is the difficult one to solve without the item getting to heavy and ugly. Probably, compression and locking rings rather than screw thread I suppose

Steven Tribe
5-Mar-2012, 04:39
As it is cold outside to-day for final garden pruning, I have done a little experimenting with the copal/sinar shutter. I have come to the conclusion that the internal spring is so solid that there is no need for a coil spring to be built into the release cable mechanism. Even if the actuating rod does stick out of the threaded sleeve a little, the friction on a short and straight release will not be enough to accidentally trip the shutter. So we are talking about a very simple design.
The attachment thread appears to be an ordinary M4 with 0.75mm pitch. Unless Sinar/Copal had their own variant? Bob S would be useful here? But perhaps these cables are still available as new items?

domaz
5-Mar-2012, 14:37
A bicycle brake cable is too flexible. It is designed to apply force in tension only.

I would suggest a different sort of Bowden cable that uses a solid inner wire designed to push as well as pull. Some control cables for automotive air-conditioners for really old cars (before digital AC controls), or the throttle cable on a lawn mower, might be something to explore. These are stiffer, of course, but if it's long enough you can still bend it around 90 degrees and eliminate transmitting movement to the camera from your hand.

McMaster-Carr sells a few models that might provide raw materials for making something. Search on "push-pull control cables".

The solid wire might be brazed or crimped in a tube to make a pushrod, but the tricky bit will be the threaded connection into the camera.



Actually the threaded connection was easy with brake cable housing. Like I said I just took the end of a standard cable release and press fitted onto the end of the housing. You can screw in a standard cable release onto the Sinar Shutter (at least on mine you can) and it stays there just fine. Agreed that bike brake cable is not the right material- I like your ideas of using other control cables. I really think this is possible- there is no magic to this cable really and it should be something that is possible to DIY.

TenOx
21-Jul-2012, 00:30
Ok, I'm all excited -- did anyone manage to make a good, working cable?
Or, find a source of supply that's not 150?

Thanks.

Armin Seeholzer
21-Jul-2012, 03:02
Ok, I'm all excited -- did anyone manage to make a good, working cable?

The original is what you are looking for, just find a used one, the older are better the the never black ones, in my opinion!

Cheers Armin