When and Why to use Variable ND Filters
We created a test of the 77mm Promaster Variable ND filter on a Zeiss 50mm Planar T* f/1.4, to help demonstrate the impact the filter can have on the image, as well as test for any color shifting, fringing, or “x-darkening” common with poorer quality filters. We’ve tried some of the other common variable ND filters, including budget filters and Polaroid, but now we rent exclusively Promaster, due to its far superior performance. This is also a good example of how adjusting f-stop can impact the depth of focus.
The shots were all done with the same settings, 125 ISO, 1/50 shutter.
The only drawback of the Promaster variable ND is endemic to all variable NDs and polarizers, as well. It tends to cut reflections, even the good ones. While this makes for a more vibrant sky, it can also make flesh tones more flat, and organic surfaces like the skin of the apple (or a person) lose luster under the higher ND levels. For staged shots where we have time to change filters, we’ll still use classic ND, but with more shoots getting smaller, we think the variable ND has earned a place in our camera bag. After using Promaster variable ND filters in the real world for almost a year, we’re happy to include them in our rental catalog.
Posted by Jon Kline