The metal aperture behind the rear lens in a 19° ED Lens Tube can be difficult to put in place when reassembling the tube after cleaning it or replacing the lenses. There are a couple of things you can do to make this process a bit easier.
Steps to Solution
- Hold the bottom aluminum casting in place when installing the lenses and aperture using either a vice or another person
- After putting the lenses in place, partially screw the castings together. This will give you enough play between the castings to put the aperture in place without knocking out the lenses. After installing the aperture, finish tightening the casting screws.