American cinematographer (Jan-Dec 1941)

Are We Afraid of Coated Lenses? By CHARLES C CLARKE, AS C. SINCE the announcement some time ago that glass surfaces could be coated with a transparent material, applied in microscopic layers or laminations, for the purpose of reducing surface reflections, it was immediately seen that this process was one which could 1 be used on photographic lenses with possible benefit. Most of the major studios proceeded to have a set of lenses or two coated with the new material. It was soon discovered that the coating did more than simply control the unwanted reflections and flare, the most apparent difference being in the added definition, an increase : of brilliance or contrast, and surprisingly enough, an ADDED transmission of light. The extra exposure amounts to about a full f-stop. The first two effects are direct results : of the anti-flare coating, for it is real ized that the interior reflections from the several elements of the modern un' coated lens kick back and forth, greying "over the shadows and blurring the sharpness of the focus. Just why an extra layer of not too clear coating applied to the several lens-surfaces should increase the light transmission is more than I understand except that the highercontrast values apparently increase the exposure. The increase of contrast and definition were values not expected and in a measure may be part of the reason why coated lenses are not more generally used than they are. I know of several instances where cinematographers have had lenses coated, but after a few days' use have returned to their un-coated lenses, except for some very long shot or an unusually-lighted scene. The manner of lighting and of developing the negative for un-coated lenses have so long been thoroughly familiar: hut it is clear that a new technic must be developed for the coated ones. This is especially true in close-up work. Even with un-coated lenses diffusion-discs, gauze diffusers, and the like, are usually used with medium close-ups and always when large close-ups are made. It would seem that the same rule should apply when using coated lenses modified, by simply adding heavier diffusion to countereffect the sharper definition of the coated lens. However, when an uncoated diffusing medium is introduced into the optical system of an otherwise coated lens, most of the benefits of the coating are lost. The quality of the lens reverts back to that of an ordinary lens. Unless the lighting-contrast is modified for use with this combination, the result on the screen in the finished production will jump from one value to another quite different when diffused and un-diffused scenes are cut together. The brilliant, well-defined image possible with the coated lens, while having an extremely long range between highlight and deepest black, is not to be confused with that quality generally called "hard" or "chalky," for the coated lens gives a long range of middle tones and "holds" detail in extreme shadows and highlights as no un-coated lens will. Though a close-up may be lighted in the extreme key, the high-lighted area renders all of the skin texture; white collars reveal their weave, and yet every detail is visible in the darkest clothes and deepest shadow. To my mind, this quality of brilliance and definition is far more apparent and valuable than the anti-flare characteristic. One must still avoid photographing into extremely strong sources of light, such as lanterns, flashlights and highly burnished metallic surfaces, though a much greater range in this respect is possible than with the un-coated lens. Several productions are now showing where use of the coated lens is evident. "Tall, Dark and Handsome," "Tin Pan Alley," "Citizen Kane" and several others are among them. A sensational example of the anti-flare possibilities is in evidence in "Citizen Kane" in those scenes in the Opera House where the camera is directed into the footlights and floodlights that illuminate the character on the stage. I have recently completed a picture which presented an interesting experiment for the use of coated lenses. The picture is "Dead Men Tell,'" the latest of the Charlie Chan series. As the title indicates, it is a murder-mystery, and calls for most of the production being photographed in extreme low key Effect Lightings. As the story permitted an unusual photographic approach, I determined to use the coated lenses for every quality they had in them. Rather than endeavoring to bring the contrast and definition more nearly to the customary values of the average pro duction, I went perhaps to the opposite extreme by striving to take advantage of all the definition and brilliance that tre coated lenses and the new Twentieth Century-Fox camera would allow. This camera, it must be mentioned, in itself permits unusually weiJ-defined photography because of the shutter placement and silent operation. The camera is not blimped, and therefore there is no need to use a glass window before the lens. In "Dead Men Tell," no diffusion was used on any scene, close-up or otherwise, except that in making a sequence of night-exteriors on a dock set a light haze-filter was used for atmospheric effect. Obviously, of course, in making some of the larger close-ups of the feminine players the strictly literal rendering of the coated lens with no diffusion might be unflattering and hence undesirable. But it seemed to me that we have at hand means by which this can be corrected even without recourse to the conventional photographic diffusion methods. Therefore I attempted in making these close-ups to control the visual effect through the light-source rather than through the lens, lighting these shots with more of a portrait-lighting style than with conventional cinematographic lighting technic. The key-light was usually a heavilysilked broadside or rifle, rather than the spotlights generally used. As is well known, the smaller the actual source from which light comes, the sharper the definition of the resulting image will be, and conversely, when the source of light is from a physically large area, the definition of the photographic image is correspondingly softer. This is heightened by the use of heavy diffusing media over the light-source, for this again breaks up the light-rays from a hard beam to a softer flood, and tends to "iron out" wrinkles and similar facial imperfections. This treatment, I found, worked excellently in making these close shots of the ladies. It enabled me to retain the brilliant photographic characteristics of the coated lens, and at the same time create an effect which presented these ladies pleasingly. In phot -graphing the male characters, especially the suspects, more conventional lighting metnods were used. Keg spotlights were employed in the usual manner, with very strong modelling. This took full advantage of the coated lens' characteristics, and gave an effect of strength and masculinity which not only contrasted usefully with the more softly-lit presentation of the ladies, but coordinated well with the dramatic mood of the story. Another modification in lighting which I found useful was the fact that very little or no front-light was used throughout the picture. For the coated lenses, I have found, have the ability of getting into the shadow's in an uncanny manner. Very possibly this characteristic is due to the fact that in eliminating internal flare and reflections, the lens-coating (Continued on Page 199) American Cinematographer April, 1941 1C>1