Please note this warning about Copal shutter failures in tech lenses and possible reasons and ways to prevent it from Capture Integration:
This email came from the Head of Technical Services at Cambo. Note that while his English is very good he is not a native speaker.
We like to share with you some experience that occurs lately more than previously.
Schneider as well as Rodenstock confirm that there is an increase of needed repairs for Copal shutters. We also notice this, where in the past the Copal shutter was a reliable product for years.
One of the possible reasons might be a different way of use by the newer generation of users
who shoot digital and may use a different workflow compared to the old style Large Format Shooters.
The traditional way of working is to open the shutter for viewing, then close the shutter before setting the shutter speed and aperture, and only then cock the shutter just before releasing the shutter. This is trouble free.
Appearantly with the workflow of digital shooting with a CCD-back always in place, it is tempting to cock the shutter directly after the shot, and perform time adjustments after that. On itselves this is OK, but once the shutter is cocked, and then the shutter opening lever is opened for viewing and the shutter speed setting ring is being used, the mechanism will be destroyed after some time. This can be noticed also because the time setting travels very difficult and stiff in that case.
So, please consider that the shutter speed setting may NOT be used when the lens is open and the shutter is already cocked.
This information applies to any lens mounted on a Copal shutter, independent of the type and make
of the camera.