This 77mm CineMorph Clear Streak Filter from Vid-Atlantic is designed to be used perpendicular to a point light source such as the sun, a light bulb, or a candle. It can create the effect of a scene or image that has been recorded with an anamorphic lens and then displayed using a complementary reverse-projection lens. This can result in streaks that are symmetric and extend horizontally from a prominent point light source to draw attention to a specific part of the frame, or to create a visually dramatic effect. Additionally, otherwise circular, out-of-focus highlights within the frame are given an elongated, elliptical shape that is also reminiscent of many wide-aspect-ratio movies recorded on film.
If an image or footage is captured with an anamorphic lens for the primary purpose of obtaining a greater aspect ratio than what is possible when only using spherical lenses on a 35mm format, the direct result will appear compressed and distorted. Projecting this compressed and distorted footage or imagery through a reverse-anamorphic projection lens allows elements within the scene to be viewed in their correct proportions. A complementary effect of this process after it is completed is the creation of blue-colored, horizontally symmetrical highlights from prominent point light sources that can extend through the frame, as well as elongated, elliptical highlights from out-of-focus point light sources such as those that appear in the background.
Many cinematographers and photographers find these effects desirable, and the Vid-Atlantic 77mm CineMorph Clear Streak Filter is intended to allow both such highlights to be easily reproduced when used with a recommended lens that does not have an anamorphic design. It features a built-in, plastic diaphragm that is protected by a layer of optical glass with an intersecting filament. The filament's action is limited to prominent point light sources and renders the streaks it creates with no color, allowing existing colors or lack of colors displayed by prominent point light sources to be maintained. Simultaneously, the plastic diaphragm's own elliptical aperture can reproduce the type of out-of-focus highlights that are associated with a traditional anamorphic process.
To minimize vignetting, a recommended lens provides a single focal length that is 50mm or greater for 35mm film, full-frame digital, or APS-C digital cameras, and can be set to an f-stop ranging from f/0.95 to f/2.8. To help ensure that the elliptical highlights are not clipped, this 77mm CineMorph Clear Streak Filter is intended for use with lenses that have 62-82mm front filter threads, while lenses with 46-62mm front filter threads can instead use a separately available Vid-Atlantic 58mm CineMorph Clear Streak Filter. CineMorph Clear Blue Streak Filters are also available, and are designed to create blue-hued streaks, which emulates the character of traditional anamorphic optics that are not designed to suppress colored streaking.
A lightweight, aluminum-alloy step-up ring is included, which can be used to adapt this filter on lenses with 72mm filter threads. Step-up or step-down rings for recommended lenses with filter threads other than 77mm or 72mm are separately available.
This filter is most effective for pictures where the light sources used to generate highlights feature a significant degree of contrast from the rest of the image. Its diaphragm, protective glass, and filament are mounted within an aluminum-alloy filter ring that can be rotated to adjust the overall orientation of the streak and elliptical highlight effects.
