Focusing Screen Chart
Caution: Sooner or later dust will find its way onto and under the {ocusing screen. Keep its surface clean using a fine dust brush designed for photographic lenses. If fingerprints or greasy marks do get onto the screen, blow gently on the surface and wipe away the marks carefully with photographic lens tissue. The rear surface of the screen is made of acryl resin. Special care should be taken to protect it from scratching or excessive pressure.
The chart at right has been prepared to assist you in choosing the right screen for the lens to be used.
Especially recommended
The image is uniformly bright from edge to edge. However, with lenses marked (*), focusing must be done on the surrounding matte area because the central
Acceptable
In actual use these screens present little obstruction, although the viewfield over the entire area is less satisfactory because of slight vignetting or moire phenomenon (in the case of microprisms). Of course these drawbacks have no effect on the image recorded on film.
Combinations represented by a blank space are unusable because of image darkening or considerable moire over the screen area.
