Movie Makers (Jan-Dec 1948)

118 MARCH 1948 (Cut on dotted line) Please mail postpaid rolls □ double 8mm., □ single 8mm., □ 16mm. (Deduct 5% on 3-roll orders.) It is understood the initial film cost includes free 24-hour processing at the ESO-S processing plant in Kansas City. □ Check enclosed □ Send C.O.D. Mail to: (Name) . (Address) (City) (State) ESO-S-828 W. 39th St.-Kansas City 2, Missouri THE RALPH R.ENOCORP. 626 W. 165 ST. . NEW YORK Send your film for free criticism or estimate Have You an Odd Piece of Unused Equipment? Dispose of it through classified advertising. The rate is ten cents a word, and there is a minimum charge of $2.00. MOVIE MAKERS 420 Lexington Avenue New York 17, N. Y. mi SELLS THE BEST.' I'm proud to present the very best in new and used photographic equipment . . . guaranteed to satisfy or your money back. President 'Cmmm 179 W. MADISON ST. CHICAGO 2. ILL. a 16mm. flywheel system is used on 8mm., the energy storage is reduced to only 25 percent, since the energy varies as the square of the velocity. A corresponding increase in flutter and "wow" should be expected, unless it is corrected by improved mechanical design. Of the projection speeds there are three possibilities to choose from: 24, 18 or 16 frames per second. Eight millimeter sound films which are made from 35 or 16mm. originals will most conveniently use 24 frame projection. Best fidelity is offered by this speed. On the other hand, old silent films which have a track added should be run at their original 16 frame speed. It has been found by experience that most amateurs project their silent films at about 18 frames per second, since this livens up the action. Data for the 18 frame speed accordingly have been taken. On new productions intended for magnetic sound the amateur will have his choice of the higher fidelity 24 frame speed, or the more economical 18 frame speed (provided his camera can be set at either one). Frequencyresponse curves for the various speeds are given in Fig. 5. While not "high fidelity" the response compares with that of super-heterodyne radio receivers. Listeners have commented that both speech and music are excellent. It is interesting to note that in tests we have recorded as high as 10 kilocycles with a 2V2 inch-per-second film speed. This is not typical, of course, but it does indicate that there is room for future improvement. The present converted unit is not operating at its best because it uses an unregulated series motor. The addition of a governor, or the use of an alternating-current motor would decrease "wow" considerably. Another standard projector which has been converted is shown in Fig. 6. A SIMPLE ADAPTER UNIT FOR 8MM. PROJECTORS An attempt was made to design the simplest possible 8mm. sound adapter unit which could be applied to 8mm. projectors. One of the designs evolved is shown in Fig. 7. All of the essential parts are fastened to a plate which may be mounted on the projector with a pair of screws. The film comes down from the optical gate, and loops up past a pair of posts which take out most of the intermittent flutter. It then is pulled through a pair of friction shoes into the sound gate. The magnetic head is mounted in a recess in the stationary shoe. Its high impedance of 9000 ohms at 1000 cycles allows it to operate directly into the amplifier grid. A pair of posts between the drive sprocket and the friction shoes bend the film to provide compliance. All posts and shoes are grooved so they cannot scratch the picture portion of the film. The film compliance and friction blocks form a simple resistancecapacitance-type filter indicated by the electrical-filter circuit at the right. The adapter unit, mounted on a typical 8mm. projector, is shown in Fig. 8. The demonstration model operates under unfavorable conditions. It uses a series-type universal motor with poor regulation and V-belt coupling. Sprockets are driven by gears, and are of small diameter (12 tooth). The intermittent mechanism gives a fluctuating load on the poorly regulated motor. In spite of these faults (many of which could be corrected in a machine designed for sound adaptation) the projector does a creditable job for voice work, and gives quality that should be acceptable for such things as amateur titling and narrative. ACKNOWLEDGMENT The author wishes to thank Ampro. Bell and Howell and Univex for generously supplying equipment used in these tests. Eight or sixteen? [Continued from page 103] entertainment to a family group in the living room of one's home. Once there are more funds available for buying 16mm. films, it is possible to blow up the mature 16mm. for audiences many hundreds in number. It is also possible to enter the commercial field or to recover part of one's expenses by selling usable footage to commercial filmers. One more reason for the use of Sixteen by those who can or are willing to afford it. is that definition, or sharpness, in long distance scenes is much better than in Eight. I have used both the 8mm. and the 16mm. widths, and these are my reactions to them. Joseph J. Harley, FACL Summit, N. J. IDEAL FOR FAMILY ... I believe that 8mm. is the ideal size for family filming because of its lower cost, and smaller size. Although the film is too small to be shown in lecture halls and auditoriums, the average filmer can show it to a group of twenty or thirty people without any trouble. We use a 39 by 52 inch screen at 25 feet from the projector and, with a 500 watt bulb, get very sharp and bright images. We have done a great deal of our filming in rugged mountain country; 8mm. equipment is much easier to handle than 16 under these conditions. The long shots in 8mm. are the least desirable of all the camera distances, as far as my own experience is concerned. In filming people and objects,