The ones that matter
- ND (neutral density): long exposures, or wide apertures in bright sun.
- Variable ND (VND): dial the strength instead of swapping filters. Cheap ones can show a dark “X” at the strongest setting and a colour cast, so favour a modest range (about 3–7 stops) from a reputable maker.
- Circular polarizer (CPL): cuts glare on water and leaves and deepens blue sky, strongest at 90° from the sun. It costs one to two stops.
- Infrared: see the infrared lesson.
- Mist or diffusion: a soft glow around highlights. A style choice, not a necessity.
A UV or “protective” filter does nothing for image quality on a digital camera. Graduated ND is better done by blending two exposures in editing.
Getting the size right
Look for the Ø symbol and a number (for example Ø49) on your lens barrel or the inside of its cap: that’s the front thread in millimetres. Buy the filter for your largest lens and use inexpensive step-up rings on the smaller ones.
Magnetic systems keep a thin ring on each lens and let the filter snap on and off, which is fast when the light is moving.
A quality checklist
- Neutral colour. Shoot a grey card with and without the filter and compare in editing.
- Coatings that resist water and fingerprints.
- A slim frame, so wide lenses don’t vignette.
- Solid build: the filter is the one thing you screw to a good lens.
A system to look at
Freewell makes magnetic ND, variable ND and polarizing filters. Its V2 Magnetic Hybrid VND/CPL covers 3–7 stops and was listed at $149.99 in October 2026, with kits above that.
StatusFreewell is a new partner and a hands-on review video is on the way. I earn a commission on purchases through my link; judge it against the checklist above in the meantime.