Which ND filters work best for Sony a7 IV landscape video?

Question

Hey everyone! I recently upgraded to the Sony a7 IV and I am finally trying to get serious about shooting landscape videos. I have been a stills photographer for years, but I am finding that managing exposure for video is a whole different beast, especially when I am out in bright daylight trying to keep that 180-degree shutter rule for natural motion blur.

I usually shoot in S-Log3 to get the most dynamic range, but even at the base ISO of 800, my footage is totally blown out without some heavy glass in front. I am currently using the Sony FE 16-35mm f/2.8 GM II, which has an 82mm filter thread. I have been looking at a few options but I am really worried about color shifts or that nasty X-pattern you sometimes see on cheaper variable NDs.

Here are a few things I am looking for:

Something that does not ruin the sharpness of the GM glass

Minimal color cast so I am not fighting magenta tints in post

A system that is easy to swap if the light changes quickly during sunrise

I have seen people mention the PolarPro PMVNDs and the Freewell magnetic systems, but I am not sure if they are worth the premium price tag for this specific sensor. Does anyone here have experience with brands that play well with Sony colors? Which ND filters have you found work best for high-quality landscape video?

MistyValley · Accepted Answer

Honestly, if you are rocking that 16-35mm GM II, you definitely shouldnt cheap out on the glass in front of it. Since the a7 IV base ISO for S-Log3 is 800, you are basically looking at needing 6 to 9 stops of ND in direct sunlight to hit that 1/50th or 1/60th shutter speed. I have been using the Freewell Magnetic Variable ND Filter System 82mm for a while now and it is a total game changer for speed. The magnetic base lets you swap between the 2-5 stop and 6-9 stop rings in seconds during a fast sunrise. Technically speaking, these use high-index optical glass which minimizes the IR-pollution and magenta shift you are worried about. Plus, because they have physical hard stops, you wont ever hit that cross-polarization X-pattern that ruins shots on cheaper variables. It is definitely worth the investment to maintain the resolving power of your GM glass.

LarisaCet · Answer

Agreed. For technical precision, check the PolarPro 82mm Variable ND Filter Peter McKinnon Edition II 6-9 Stop because its fused quartz glass preserves the MTF performance and corner sharpness of your GM lens.