Magnetic ND Filter Systems: Are They Worth It Over Screw-In Filters?

A magnetic ND filter system lets you attach and swap neutral density, polarizing and other filters in seconds using a magnetic adapter ring that stays on the lens. It is a good choice for photographers and videographers who change filters often, as long as the system offers good optical glass, strong magnets and the ring sizes you need.

How Magnetic Filter Systems Work

You screw a thin adapter ring onto the front thread of the lens. The filters have a matching magnetic frame and snap on instantly. Stacking is possible, so you can combine an ND with a polarizer or a graduated filter. Compared to screw-in filters, there is no cross-threading, no stuck filters, and no fiddling in cold fingers. Compared to square filter systems with holders, it is more compact and quick, though less flexible for graduated filters, which are limited to circular formats.

Why ND Filters Matter

ND filters reduce light without changing colour. Videographers use them to maintain a 180-degree shutter angle (a shutter speed about double the frame rate) in daylight while keeping a wide aperture. Photographers use them for long exposures that smooth water and clouds. Variable ND filters offer a continuous range in one filter but can show cross-polarization bands (an X pattern) at extreme settings and slight colour shifts; fixed-strength NDs avoid this.

Evaluating Quality

• Glass and coatings: Multi-coated optical glass reduces flare, ghosting and colour casts. Cheap resin or poorly coated glass softens detail.
• Colour neutrality: Heavy NDs, such as 10-stop, can introduce a colour tint. Check reviews for neutrality and know that you may fix residual casts in editing.
• Magnet strength: Weak magnets let filters slip, especially on shooting rigs or gimbals.
• Adapter thickness: A thick ring can vignette on wide-angle lenses, so choose slim designs for ultra-wides.
• Weather sealing and materials: Aluminium frames with durable finishes withstand outdoor use.

Common ND Strengths

Sizing and Compatibility

Buy the ring size that matches your largest lens filter thread, then use step-up rings for smaller lenses if needed. Make sure the system sells filters in the diameter you want, such as 67mm, 72mm, 77mm or 82mm. Some systems provide a universal kit with multiple rings. Check compatibility with lens hoods: many hoods cannot stay on once the adapter is fitted, or the filter must go behind the hood. Test on your widest lens to confirm no vignetting. A magnetic ND filter kit that includes a case and several ring sizes is often the best way to start, and a magnetic circular polarizer pairs well with ND for water and foliage.

Magnetic versus other filter types

Screw-in filters are cheap and secure but slow. Square systems with holders suit large landscape workflows with graduated filters, but they are bulky. Magnetic systems fall in the middle: fast, compact and ideal for video, travel and drone cameras. Some drone ND filters are magnetic or clip-on to maintain balance on the gimbal, so ensure weight and balance are within the manufacturer’s recommendations.

When using magnetic filters on mobile phones or cameras with sensitive electronics, keep strong magnets away from credit cards and medical devices such as pacemakers, and follow the manufacturer’s guidance.

Choosing strengths for video versus stills

Video shooters usually carry a set of ND filters from roughly 2 to 6 stops to hold a steady shutter speed as the sun moves, whereas landscape photographers want the 10-stop and higher strengths for extremely slow exposures. A single variable ND is attractive for convenience but check the stated usable range to avoid the dark cross pattern at the maximum density. If you shoot both, a combined kit of a couple of fixed strengths and a polarizer covers most situations without bulk.

Care and handling

Keep the filters in a padded case, clean them with a blower and a microfibre cloth, and avoid touching the glass. Dust and fingerprints show up on long exposures, so wipe filters before use. When shooting with strong ND filters, focus and compose first, then attach the filter, as the viewfinder will go dark. Cover the viewfinder or use a cap to prevent light leakage on DSLRs during very long exposures. A padded filter case prevents the scratches that ruin optical coatings.

Exposure workflow with strong ND

Start by composing and focusing without the filter, switch the lens to manual focus so it does not hunt, then attach the filter. Use a base ISO, set your aperture for sharpness, and let the shutter speed run long. A 10-stop filter turns a 1/60 second exposure into roughly 16 seconds. Use bulb mode or a remote, and check the histogram. Because many cameras meter poorly through dark filters, take a test shot, then adjust.

Frequently Asked Questions

Do magnetic filters fall off?

Good ones hold securely in normal use. Check magnet strength reviews, and be careful with sudden movements or when filters are stacked.

Can I stack multiple magnetic filters?

Often yes, but stacking increases vignetting risk and potential flare. Use the thinnest frames.

Are magnetic filters as sharp as screw-in?

Optical quality depends on the glass and coatings, not the mounting method. Choose a reputable brand with quality glass.