Sinar Copal Shutter

[Geoffrey_1456]

Bob,

Comparing Sinar Copal shutter and Compur or Protonor shutter is like comparing apple and orange. Their vibration levels are NOT on the same magnitude. When you fire a Sinar Copal shutter, you feel like you have had your lens mounted on 10 Compur #3 shutters and fire them all together. It's Load, period!

Kevin,

If your Sinar Copal shutter has excessive vibration during exposure, you might want to have it checked by your local Sinar dealers or the Great Steve K. Grimes. It might just need a lube job. I have used my Shutter Copal shutter and exposed a number of 8x10s (with C. P. Goerz Dagor 420/7.7) and have NOT yet had any sharpness issues. Sinar Copal shutter has been in the business for quite some time. If it could cause sharpness problems, it would have been put out of business long time ago. In fact I haven't heard complaints from my friends. They still use Sinar Copal shutter for their commercial assignments in New York City. Take your sharpest lens and try it. I wonder where those experts go? Cheers,

[Bob Salomon]

I defy Kevin to show us shots taken with a sharp lens in a modern between the lens shutter and the same lens in NF mount that illustrates his point.

Having sold tens of thousands of lenses in and out of shutter for all LF and many MF cameras we are yet to have a single person in the past 25 years make or illustrate the point he makes.

Yes the behind the lens shutter is not the same as a Copal/Compur/Prontor Professional/Rollei Linear Motor/Horseman ISS shuttter.

Sounds more like an improper tripod.

[Kevin J. Kolosky]

I own and use a Zone VI heavy duty tripod with the spiked feet. it doesn't move. I practice what I preach and do not own a shuttered lens to do the test. Perhaps you would like to send me one Bob. Kevin

[werps]

Make sure that your Sinar shutter isn't bent and that the groove it slides into is clean. It should slide in very easily. Never force anything on a Sinar... IT WILL BREAK!!!. I love my Sinar and its' components but they are more fragile than they need to be, so always proceed with caution when changing or removing parts.

As for the vibration thing,if it vibrates enough to mess up a photo then it's broken. No lens shitter that is in proper working order would cause enough vibration to cause a lack of shrpness in a photo, especially not a Sinar

[Kevin J. Kolosky]

The winner of the Prize is Geoffrey. Thanks Geoffrey for answering the question that I asked. I took the two rubber pieces out of the grooves and now the shutter fits right in there and locks up tightly. I will replace the rubber pieces with a couple of pieces of felt,which should serve as well in keeping stray light out but will not be so thick as to keep the shutter from fitting on the camera.

Thanks again Geoffrey. And thanks to everyone else as well. That is what makes this forum great, to express opinions whether agreed upon or not.

Kevin

[adam friedberg]

you should call sinar bron. they are very helpful. removing rubber strips may be the wrong answer - there's a good chance sinar meant them to be there. when you speak with them ask about the proper technique to use the shutter. i have seen a lot of people do it wrong and think the shutter was broken until they learned. the way you press the cable release is very important. thousands of top pros use this shutter successfully with no vibration problems and have been doing so for decades. actually this is the first time i've heard a complaint about shutter vibration without being specifically about multiple exposures.

by the way, what is a better solution, regardless of timing, than a mechanical (or electronic) shutter?

[Bob Salomon]

What is even more confusing is that with all of the people who have attended Brooks Institute of photography and who probably also had the same instructor this is the first time this has been brought up.

Of course not using a shutter can cause all kinds of other problems. Shooting at small enough apertures to do daylight exposures on normal speed films would usually require a very small aperture to allow accurate manual timing. This, of course, is a perfect way to lose quality due to diffraction and, possibly, vibration during that extended period.

of course doing this inside with flash requires open flash and possibly multiple pops in a totally dark room. Vey inconveniet way to work.

[Kevin J. Kolosky]

Once again, everyone is entitled to their opinion. Perhaps the rubber is there to dampen vibration. But again, the shutter (a F4 model) would not fit on the 8 x 10 camera without the rubber coming off. I have now put felt in the same place as the rubber and it works fine. Its off to the Owens valley on Wednesday. By the way, does anyone know how to keep a sinar 8 x 10 bellows from sagging. I don't see anything listed in their catologs. Kevin

[QT Luong]

The shutter (mechanical) with the least vibration is the Prontor Professional and many studios do multiple pops on this shutter with no sign of ghosting

Because it is self-cocking, the Prontor requires more force than a standard Copal. I have found the vibration induced by the same cable release to be significantly higher. It could be that the shutter itself vibrate less, but I am not sure how significant this fact is, given the previous one. Correct me if I am wrong.

[Bob Salomon]

"Prontor"

Prontor Press or prontor Professional?