Neutral density (ND) filters are a requirement for shooting smooth video in bright light, and circular polarizing (CPL) filters are often needed to improve contrast or darken a bright sky — but what if you need both? A new clip-on phone camera filter answers that question, by combining both ND and CPL filters into one. The product is the latest from Sandmarc, a company that specializes in filters for GoPro and DJI and also has a line of mobile lenses, including an anamorphic cinema lens for iPhone announced earlier this year.
The hybrid filters are available only in a three-pack, offering ND strengths of four, five, and six stops for a total price of $130. Each filter uses multicoated anti-reflective glass and is housed in an aluminum frame. Like a standard polarizer, the frame can be rotated to change the angle of polarization, strengthening or weakening the effect to get the desired results. Polarizers don’t just cut back glare, they can also help you “see through” reflections on glass or water.
NDs are especially important for phone videography as phone cameras have fixed apertures, leaving shutter speed as the only variable for compensating for bright light. Unfortunately, the fast shutter speeds required on a sunny day cause video to look jarring. An ND filter darkens the image, letting your phone use a slower shutter. This allows for some motion blur and creates a more natural look that mimics how our own eyes see motion, thus making video easier to watch.
The filters attach to a phone using a simple clip, which is included. In addition to being compatible with iPhones back to the iPhone 4, Sandmarc also says its system will fit many Samsung Galaxy, Google Pixel, and Huawei phones. Additionally, the filters can be mounted directly to Sandmarc’s mobile lenses, which include wide, telephoto, and macro versions in addition to the anamorphic lens.
Mobile photography filters are not new, but they seem to be having a surge in popularity right now — at least from a production standpoint. Mobile lens maker Moment also announced a line of filters this week, offering separate ND and CPL variants with ND strengths ranging from two stops to six.