International photographer (Jan-Dec 1934)

Eight T he IXTERNATI O X A L PHOTOGRAPHER September, 1934 is not recommended. However, in this matter each amateur must work out his solution, for every make and type of camera presents a different problem. Naturally, light must be excluded at the connection where the camera lens and 'scope eye-piece meet. In temporary cases this is easily accomplished by wrapping black cloth around the connection several times so that no light is permitted to enter except that which is intended to traverse through the microscope from below. Or a tube can be rolled from stiff cardboard which snugly fits over both lens and eye-piece. A special "adapter ring" is available for the Leica camera which is placed over the eye-piece of the 'scope and fastens to the lens by means of a set-screw. This makes a perfect connection and should be considered by all who own a Leica. Illumination we must have for our exposures. Just what type and how much is again a matter for the individual worker to decide, for conditions will vary greatly in each case. The most satisfactory type of light is of course the carbon arc. A number of excellent microscope arc lamps are on the market, should the amateur care to go into this work sufficiently to make their cost worth while. An arc lamp can be made, using small "pencil" carbons and drawing only a few amperes, but the beginner had best pass this type of illumination up to begin with, anyway. The tungsten type of light seems to have every desirable feature — intensity, safety, and low cost. A lamp of about 100 watts will work nicely. It should of course be contained in a well ventilated lamp house to insure a concentrated light source at the microscope mirror. Lamps of less intensity are likely to cause the exposure to be unnecessarily long. It is necessary to see that the light is striking the microscope mirror squarely, and that the mirror is adjusted so that the utmost illumination is secured on the specimen. In the vast majority ot cases, the microscope must be focused visually, then after focus has been carefully established, the camera is placed over the 'scope for the exposure. Because of this, inanimate specimens only can be attempted (except in the case of the special Leica and Contax attachments referred to previously). The choice of sensitive material (film or plate) should be given careful consideration. For simple subjects, a fine-grain orthochromatic film is suggested. If it is fast, all the better, for exposures can then be shortened considerably. If the specimen is stained — and most microscope slides are — a panchromatic emulsion is indicated. Two factors should be kept in mind as far as the emulsion choice is concerned: speed and grain. Speed is highly desirable to cut down exposures, and fine grain is necessary for small negatives, which are usually used for photomicrography, because enlargements will subsequently be made. Contrast is another desirable feature if it can be had in combination with the other requirements, for it assists splendidly to bring out the tiny details in the enlargement. Amateurs who possess miniature cameras which use standard 35 mm. cinema film will find in DuPont Micropan and Eastman Panatomic two ideally suited films for their purpose. Roll film camera owners can use the Eastman Panatomic without hesitancy. Agfa Plenachrome or Superpan cinema and roll film are likewise excellent. So are Perutz Neo-Persenso and Peromnia, Selochrome, Gevaert Panchromosa, Voigtlander — -but why go on? Each amateur has his pet films to work with, and all are good. As for exposures — ah, that is a mystery. It can readily be understood how impossible it is for anyone to expect to guess the exposure — or expect anyone else to. As each condition is different — light source, type of light source, microscope, type of objectives and eye-pieces, magnification, specimen, color of specimen, and type and speed of emulsion — it can be seen that there is but one accurate method of learning the correct exposure to give — make a test strip of a series of exposures, each at a different exposure. On developing this test strip it becomes easy to note which exposure is the properly exposed one. This one, then, is the guide, and on referring Micro-lbso attachment for coupling Leica camera to microscope. to the notes made while the test strip was being exposed, we know just how long to expose for. Once a few such tests have been run off, the amateur can readily judge for himself the correct exposure in future work. There is such a thing as using an exposure meter but the results are not always reliable nor constant, hence the test method is by far the most satisfactory, if a bit round-about. These few words are written merely in an attempt to interest the amateur photographer in coupling his camera to a microscope. For further suggestions, the reader is referred to various books and pamphlets on the subject. The Eastman Kodak Company has a dandy for fifty cents. Be sure to get a copy. No one should hesitate in these days of enlightenment to make bold explorations with his camera, large or small. The camera can be used for so many fascinating activities that it seems strange that ninety per cent of the camera owners confine their photographic activities to the usual run of snap-shooting. The camera as an instrument is capable of far more, and it would appear that the amateur is cheating himself by not using his camera to its utmost capabilities. SPECIAL MODEL LEICA CAMERA The new model FF Leica is being announced by E. Leitz, Inc., 60 East 10th Street, New York City. The model FF Leica is basically the same as the famous model F excepting that the film capacity is 33 feet (enough for 250 exposures instead of a little more than five feet in the regular Leica, giving up to 36 exposures). Aerial photographers will welcome this new model, for it eliminates the need for reloading after every 36 exposures. Natural color photographers will find it of great value in their work, for it permits a greater range of pictures to be made without opening the camera. It shorter lengths. For copy work, the model FF is without a peer, for its film capacity permits the copying of many pages successively without interruptions. In short, the model FF Leica is ideal for all photographers who have need for making more than 36 exposures per loading. The new Leica model possesses all the features of the model F Leica, slow shutter speeds, magnified range finder, etc. Two film magazines are used, thus making it unnecessary to rewind the film back after exposure. Any of the Leica lenses are interchangeable on this model. Accessories include an Eveready case, special is likewise useful to press and candid photographers, for ^m trimming guide, and spare magazine. often they are required to make a complete series of Circular 7454 describes the new model FF Leica. pictures in rapid succession without time to re-load A copy will be gladly sent to all those requesting it. Please mention The International Photographer when corresponding with advertisers.