Rodenstock Imagon 300mm: Cleaning a Dial Set Compound Shutter
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
This 300mm Rodenstock Imagon lens needed a minor cleaning to restore operation as it has been in storage for around thirty years unused. This lens with its diffusion disks was the classic soft focus lens for large format photographers. These are found in various shutters, this one is mounted in a dial set Compound shutter.
A little info on the dial set shutter: While most modern shutters use a gear train escapement to retard the closing of the shutter blades, the dial set shutters used a small piston in a cylinder (shown at the top of the shutter in photo three) to slow things down.
Photo three also shows the shutter with the blades open and visible are the twenty diaphragm blades (glad I don’t have to remove and install these on this shutter) that form an almost perfect circle.
As seen in photo four, the inside of the shutter is fairly simple as there are no speed controlling parts inside.
The video shows the speed control cam, a thin brass part that contacts the piston control mechanism to regulate the various shutter speeds. If you look carefully at the control cam, you can see small dots that indicate shutter speeds. If needed, you could swage the cam at these spots to adjust each shutter speed. The final photo shows the cylinder with the piston removed.
These types of shutters came into being around the turn of the twentieth century and were made, in the large sizes especially, into the 1960’s.
If anyone feels they need to own this Imagon, please contact me as it is time for it to go to a new home.
