Two new techniques have been applied to the viewfinder of recent SLR camera“Minolta XD-s”. One of them is a new focusing screen named“Acute Mat”. The microscopic conical prisms of 20μm in diameter are distributed uniformly all over the screen surface. These microscopic prisms provide more brightness and clearness for observation through a finder, and also more easiness for focusing than the conventional screen. Another technique is the new eyepiece which provides the adjustable dioptric value for viewfinder. In the case of viewfinder equipped with a conventional eyepiece, the dioptric value of the finder is fixed to some standard value. However the viewfinder equipped with the new eyepiece gives adjustable dioptric value within the range from -2.7 D to+0.8 D. With this feature, a sharp finder-view has become available even to the people of slight myopia for presbyopia. This report outlines the principles of these new techniques.
