When I finished building my Konstruktor last week, I found the viewfinder very dark. Several minutes after the Konstruktor was built, I decided to take it apart again to work on this problem.
The viewfinder problem is caused by a piece of glass above the mirror, which in the case of the Konstruktor, is made out of plastic. Fortunately I had an old non-working Yashica SLR laying around so I decided to see if I could remove the mirror and place it in my Konstruktor. After I broke my Yashica apart, I soon discovered that the mirror was smaller when compared to the Konstruktor. Thankfully, I also got to remove the mirror holder from my Yashica so that it can fit inside the Konstruktor.
In order for it to fit perfectly, I had to remove two tiny bits from the holder so that all the screws were in the right place.
I am very satisfied with the end result and I really didn’t expect it to be this good. First picture is of the viewfinder as it was before and the second picture is how it turned out to be.