I'm a new Blad user. When I look thru viewfinder I see a small black spot. I gently took it apart and cleaned any surface that I thought responsible but no luck. it appeared that without the magnifier, I did not see any spot but when I added the magnifier I did. It hasn't affected any photos but it bothers me. I thought i cleaned the magnifier but no? Any suggestions besides telling me I'm overly concerned?