Motion Picture Herald (Jan-Mar 1956)

As we said before, the cylindrical CinemaScope attachment is similar to a simple telescopic system such as is used in opera glasses. But, as in opera glasses, the distance between the front and rear elements must be changed to correct for the distance of viewing, or the distance of projection throiv. All cylindrical anamorphic attachments have such an adjusting device, generally consisting of a split housing, threaded together so that the front part of the housing with its front glass element, may be brought closer to the rear section without changing azimuth relation. Cylindrical anamorphic attachments have pre-calibrated markings on the barrels, indicating the setting for various projection distances. However, it has been found in the field that many of these markings are only approximate and that a more accurate means must be used in order to insure proper setting and proper focusing. In a complete CinemaScope lens system there are two control points that must be adjusted in order to obtain the best focus for a picture on the screen. The anamorphic attachment must be adjusted to produce equal sharpness for horizontal and vertical objects. The projection lens must be adjusted to give equal sharpness over the entire field of the picture. If by any chance, the anamorphic attachment is improperly set, then it becomes impossible to bring the entire picture into good focus no matter how much the projectionist may “ride” the focusing adjustments. TESTING LENS SETUP It is to be feared that conditions such as this exist in many installations and for that reason a detailed step-by-step procedure is given below on the method to be used in adjusting cylindrical anamorphic attachments. Once they are set properly, no further adjustment should be necessary, unless they are moved to another theatre, or are taken apart for cleaning, etc. Since it is necessary to check vertical and horizontal focusing, and sharpness and overall field under actual operating conditions, target film with horizontal and vertical lines or designs should be used as a test film. The SMPTE can provide CinemaScope test film with such designs. Loops of this film can be used ; however, a roll of film would be preferable, since the heat of the arc spot may cause a loop to curl beyond the normal amount when it is run repeatedly over a long period of time. Here is the procedure for adjusting cylindrical anamorphic attachments: 1. Thread up the test film in the projector. 2. Install the back-up projection lens only in the projector and focus the target film as sharply as possible on the screen. 3. Examine the picture on the screen from a close-up position to determine how New film techniques, in the great new pictures now being released, put new depth and clarity on the print. Make sure your prime lens can transmit all this new brilliance, color and vivid detail onto your screen. More than ever, these great movie advances are bringing customers out of the home and into the theatres again. Assure profitable repeat patronage with B&L Super Cinephor Lenses . . . for today’s most thrillingly vivid screen images of all 35mm releases. SEE THE BIG DIFFERENCE. .. FREE DEMONSTRATION! Write, wire or phone for Catalog E-123 and for free demonstration. Bausch & Lomb Optical Co., 67903 St. Paul Street, Rochester 2, N. Y. Phone: LOcust 3000. (In Canada, General Theatre Supply Co., Ltd., Toronto.) Academy of Motion Picture Arts and Sciences Honorary Award for Optical Service to the Industry .w BAUSCH & LOMB I'yi^ BETTER THEATRES SECTION 17