WHAT ARE LENS FILTERS?
Lens filters are photography and cinematography accessories that are used with a camera to create a desired effect in the image. They are made of transparent or translucent glass (or resin) and are placed in front of a lens, either by attaching to the camera or by holding it in place manually or with an articulating arm. When placed in front of the camera lens, lens filters can block or filter out light, change the characteristics of the light passing through the filter, add colors to the image, or add special effects to the image.
HOW DO LENS FILTERS WORK?
Since lens filters are just pieces of glass or other hard transparent materials, they alter how the light passes through them into the camera sensor. Depending on the type of filter or the angle of the shot, the light will behave differently. In the case of a color filter, certain color wavelengths of light are blocked out from reaching the film. For example, when using color film this works very intuitively, in which a blue lens filter will minimize the passage of red, orange, and yellow light and create a blue tint on the film.
Another way filters work is through the principle of refraction. In scientific terms, refraction is the change in direction of a wave passing from one medium to another or from a gradual change in the medium. While refraction of light waves is the most popular form, you can observe refraction in sound waves and water waves as well. Think of what happens when light passes through a prism, that’s because the light is being refracted, or filtered, through the glass producing the rainbow of colors. Lens filters use refraction to alter the light wave passing through it to produce the desired effect, which could be anything from blurring to lens flares.
USING LENS FILTERS IN CINEMATOGRAPHY
Since lens filters are broadly used in both photography as well as filmmaking, there is no shortage of options available for the aspiring photographer or filmmaker. But since here at CinePacks we focus on cinematography, we’re going to stick to lens filters that are commonly used in film and video production. Here’s just a few types of some of the more popular lens filters for cinematography.
Polarizer filters consist of two sheets of glass with a thin layer of polarizing material sandwiched in between. They are used to eliminate the glare and reflection from water, glass, and other reflective objects, thereby enhancing the colors and saturation of your shots. I’m sure you’ve seen polarized sunglasses in the store, these do the exact same thing. Because polarizer filters enhance color saturation, they’re great for cinematography because they can give you bluer skies, clearer water, deeper shadows, and more vibrant clouds in your outdoor shoots. And for indoor shoots they’re great at reducing the glare that might be coming from a window or other reflective surface.
NEUTRAL DENSITY FILTERS
Neutral density filters, or ND Filters, reduces or modifies the intensity of all wavelengths, or colors, of light equally, giving no changes in hue of color rendition. In other words, ND filters minimize the amount of light entering the lens, therefore darkening your image without losing any of your colors. ND filters are great for cinematography because they prevent overexposure, making it possible to maintain a shallow depth-of-field and a large aperture even in bright environments. Exquisite film director Ridley Scott is a master at using ND filters, and has used them in more than one of his films.
SPECIAL EFFECTS FILTERS
You might think there’s an abundance of lens filters for special effects on the market today, but surprisingly most of them are not in use anymore. With advances in digital technology, most special effects are now added in during post-production. But that doesn’t mean special effects lens filters have completely gone by the wayside.
One of the most popular still being used today is the split-focus diopter, a lens filter that allows an image to have two competing focal points. This unique lens filter consists of a half-convex glass that is placed in front of the camera’s main lens to make half of the lens nearsighted. This allows the lens to focus on a plane in the background and the diopter on a foreground element. For cinematographic purposes this can be a valuable accessory since it allows for subjects in the foreground and background to be kept in focus at the same time. Plus it can produce some pretty cool effects like image blurring and distortion. These special effects filters are so popular that you’ve probably seen it in a number of different films and didn’t even realize it. Split-focus filters have been used in many classic films such as All The President's Men, The Untouchables, and Reservoir Dogs.
LENS FILTERS FROM CINEPACKS
Lens filters from CinePacks allow you to take your next film or video project to the next level. Our Split Filter Kit includes all 3 strengths of our split filters to give you all ranges of in-camera lens distortions and creative ghost blur effects. Which means you can now produce incredible special effects in real time, saving you time and money by not having to add them in digitally during post-production. With the introduction of the world's first and only handheld split diopter effects filter, CinePacks has just made adding special effects to your project super easy regardless of the shooting situation or environment