While looking at cameras on the web yesterday, I came across a blatantly false claim by Sony. They wrote about the Sony Alpha DSLR camera:
"This changes everything.
Shoot with unprecedented speed and precision thanks to Sony's revolutionary Translucent Mirror Technology™. While traditional DSLRs depend on a reflex mirror to flip up and down with every shot, Sony's award-winning technology changes all that with its fixed-position, translucent mirror design…"
That statement is definitely false. The first camera incorporating such a design was the Canon Pellix. The Pellix was first marketed in 1965. It was Canon's first 35mm Focal-Plane Shutter SLR Camera with TTL metering. It was also the first commercial production SLR that incorporated a fixed pellicle mirror. It employed a super-thin, semi-transparent film only 20/1000 mm thick that was used as a fixed mirror.
The Leica connection to all of this is the fact that the Leica Visofelx III was also available with a pellicle mirror. This was a special modification by Norman Goldberg. Goldberg is perhaps best known, in the Leica world, as the creator of the Camcraft N-5 electric motor drive for the Leica M2 and MP. However, also to his credit were several other inventions for Leicas and other cameras. The clip he designed to permit wearing an M Leica on the belt was widely used. He also offered a modification of the Visoflex reflex housing, involving either a prism or a pellicle mirror.
Pellicle mirrors never reached any nominal success; the main reason being that part of the incoming light is permanently diverted to the viewfinder, effectively lowering the speed of the lens in use. In addition, these mirrors are quite delicate and very difficult to clean. Cleaning, on the other hand, is important because any dust, smudges or other dirt would adversely affect image quality since the mirror is in the lightpath from the lens to the film or sensor.
In view of this is seems strange that Sony would even market a camera of this type and it is equally strange that they have to accompany it with obviously false claims.