Before we go on with the lower part, we want to find out about any problems in the middle, the longest, section.

Since there are several rings with different diameters, we needed once again a home made tool. One wooden holder can be used for three steel strips of various lengths.

One side of this section was taken apart without serious problems. However this is not what we expected in a “simple” extension tube. It’s a system of two lenses placed in a frame that can be adjusted excentrically from the center. Both lenses consist of two pieces each, glued together with a naturel resin, known as Canada balsam. The glued surfaces seem free of pollution.

This is the frame for the lenses. Note the excentricity of both tubes.

This part was cleaned and mounted again.

At the other end one lens remains to be taken out and cleaned.

Will continue.