ND Filter vs Variable ND Filter: Key Differences
By Urth USA | Published: 2026-10-17
Category: Comparisons
Compare fixed ND and variable ND filters: learn when each excels, the trade-offs, and which one suits your photography style.
Quick answer
Choose a fixed ND filter when you need predictable, repeatable density for long exposures or multi-shot stacks. Choose a variable ND filter when you need fast, on-the-fly exposure adjustment for video or changing light. The trade-off is convenience versus optical consistency.
How Fixed ND Filters Work
A fixed ND filter has a single, unchanging density—for example, a 3-stop or 10-stop filter. You screw it on, set your exposure, and shoot. Because there are no moving parts, the optical path is simple, and you avoid any risk of uneven darkening or cross-polarization artifacts. This makes fixed NDs the go-to for long-exposure landscapes, architectural studies, and any scenario where you need consistent results across multiple frames.
How Variable ND Filters Work
A variable ND filter uses two polarizing layers that rotate relative to each other, letting you dial in anywhere from 1 to 5 stops of light reduction. The Urth Variable ND2-32 Filter Pro, for example, offers seamless 1–5 stop adjustment. This flexibility is invaluable for video work where you need to maintain a specific shutter angle while the sun shifts behind clouds, or for hybrid shooters who switch between photo and video without swapping filters.
Optical Quality and Limitations
Fixed NDs generally deliver the best optical quality because the glass is optimized for one density. Variable NDs can introduce an X-shaped cross-polarization artifact at the strongest settings, especially with wide-angle lenses. The Urth Variable ND2-32 Filter Pro uses precision SCHOTT B270 glass and CoraNano™ Max 34-layer dual-side coating to minimize reflectivity and maintain True Color transmission, reducing but not eliminating the X-effect at maximum density. If you shoot at 5 stops often, a fixed ND may be more reliable.
Convenience and Speed
Variable NDs win on speed. With a twist of the ring, you adjust exposure without removing the filter. The Urth Magnetic Variable ND2-32 Filter Pro adds a Magnetic-Lock mount, letting you attach and detach in seconds. This is a game-changer for run-and-gun video or event photography. Fixed NDs require you to stop, swap filters, and re-compose—slower, but more precise for planned shots.
Trade-Offs at a Glance
- Optical Consistency: Fixed NDs deliver uniform density across the frame; variable NDs can show uneven darkening at maximum stops. For critical long exposures, stick with fixed NDs.
- Speed of Adjustment: Variable NDs let you change exposure by rotating the ring; fixed NDs require swapping filters. For video or fast-changing light, variable NDs save time.
- Build and Mount Options: Screw-on variable NDs like the Variable ND2-32 Pro are compact and secure. Magnetic versions like the Magnetic Variable ND2-32 Pro add quick-attach convenience. Choose magnetic if you frequently switch filters; choose screw-on for a lower-profile, always-on setup.
Two Variable ND Options Compared
- Variable ND2-32 Filter Pro: Precision 1–5 stop light reduction, SCHOTT B270 glass, CoraNano™ Max 34-layer dual-side coating, True Color control, ultra-low reflectivity. This is the standard screw-on variable ND for photographers who want reliable color and sharpness across the adjustment range, without needing a magnetic system.
- Magnetic Variable ND2–32 Filter Pro: Precise 1–5 stop light reduction, CoraNano™ Max coating, German SCHOTT B270 glass, patented VND Magnetic-Lock mount, included Magnetic adapter ring. The magnetic mount lets you swap between this variable ND and other magnetic filters in seconds, ideal for hybrid shooters who need to change setups fast.
Which ND Filter Should You Buy?
Best for
- Landscape photographers who shoot long exposures and need repeatable, artifact-free results
- Videographers who need to maintain a fixed shutter speed while adjusting exposure on the fly
Not for
- Shooters who require absolute optical consistency at maximum density (choose a fixed ND instead)
- Those who rarely adjust exposure mid-shoot and prefer a simpler, one-density filter
