21 May 2025

By Chris “The Drone Geek” Fravel

The DJI O4 Air Unit Pro has been a significant step forward for FPV video, offering a larger sensor, D-Log M, and improved stabilization. For pilots looking to maximize the potential of this system for professional-quality footage, accessories become crucial. One such essential accessory is the Freewell Standard Day 4-Pack of ND Filters, designed specifically for the DJI O4 Air Unit Pro. These filters offer a practical solution for managing light and motion blur in various shooting conditions.

ND Filters Explained

Neutral Density (ND) filters reduce the amount of light entering the camera, preventing overexposure and allowing for the use of wider apertures or slower shutter speeds. They are identified by numerical values (e.g., ND8, ND16), with higher numbers indicating greater light reduction. ND filters are vital for shooting in bright conditions and for controlling motion blur.

Motion blur, the streaking of moving objects, is controlled by shutter speed. The 180-degree rule (shutter speed denominator = 2 x frame rate) provides a natural look. Slower speeds increase blur, while faster speeds decrease it.

Freewell Standard Day 4-Pack: Key Features and Benefits

The Freewell Standard Day 4-Pack includes ND8, ND16, ND32, and ND64 filters, providing versatility for different lighting scenarios. The pack comes with a protective case and a microfiber cloth.

Installation is simple: align the filter with the camera housing and slide it into place until it clicks. Removal is equally easy with a gentle push on the bracket.

My Experience

The Freewell Standard Day 4-Pack performed as expected, with accurate filter densities. The easy installation is a notable benefit, and the filters significantly improved the footage quality in bright sunlight with the O4 Air Unit Pro. They are essential for both exposure control and achieving desired motion blur effects in FPV videos, which often feature rapid movement.

Freewell is a reputable manufacturer of drone filters, and this 4-pack is a valuable addition to the O4 Air Unit Pro, especially for those seeking professional-looking results.

If you’re interested in purchasing this filter pack, please consider using my affiliate link by clicking here. I only recommend products I have tested and believe in. Your support helps me continue to provide valuable content.

I highly recommend Freewell’s filters and accessories. The Standard Day 4-Pack for the DJI O4 Air Unit Pro is a worthwhile investment at around $50, offering excellent value compared to competitors.

For more articles like this, check out Fravel’s Footnote on The Droning Company. You can also find more of my content on my blog and YouTube channel, “The Drone Geek.”