“The system for changing the eye-distance is blocked and there are loose parts inside. The bino has fallen, a dent in the case proves this. Looking back from the 100 mm’s you see a damaged prism.”

We are certainly aware of the fact that this optic represents a very high value. Check Ebay and you see what I mean. However this piece already showed signs that it had been opened before. So the owner asked us to try to restore his master piece.

Some parts are already removed. Once the frontplate was removed we gathered all the loose pieces inside. Besides one screw, we also found a lot of glass.

So we had the courage to take it apart completely. The prisms are mounted in frames, which can only be placed in one specific alignment, as they have tiny pins for centering.

Here you see the two prisms, each mounted in their own frame. After marking the right position, the frames were removed to gain access to the system for adjusting the eye distance.

Old thickened grease and some small glass parts, blocked the system, so this part was cleaned, polished and greased.

The result: the mechanisme works perfectly. The pieces of glass came from a part of one prism which is used to fix it in the frame. We removed all loose glass parts and put the prism back, using a flexible compound. Now all problems were solved, a last cleaning and a prudent mounting of all parts, brought us to the final test.

The 25×100 is aimed at a fine tower in Middelburg, Holland.

This is the result. See also our Testsite in Optics.