NiSi P49 Filter Holder: 40.5mm vs 46mm Adaptor Guide
By NiSi Filters Australia | Published: 2026-11-03
Category: How-to Guides
Learn how to fit the NiSi P49 filter holder to your compact camera and choose between the 40.5mm and 46mm adaptors with this step-by-step guide.
Quick answer
To use the NiSi P49 filter holder on a compact camera, first check your lens filter thread size. If it is 49mm, the holder mounts directly; if it is 40.5mm or 46mm, you need the corresponding NiSi adaptor to step up to 49mm.
Why the adaptor size matters for compact cameras
Compact cameras often have smaller filter threads than DSLR or mirrorless lenses, so the P49 system uses step-up adaptors to bridge the gap. The 40.5mm and 46mm adaptors are both made from aluminum alloy and simply screw onto your lens, converting the thread to 49mm so the holder can attach. Choosing the wrong size means the holder won't seat properly, which can cause vignetting or prevent rotation. Always verify your lens thread before ordering—it's usually printed on the lens barrel or front cap.
When to expect vignetting
The P49 holder is designed for compact cameras, but NiSi notes that some vignetting may occur on wider lenses. This is because the holder adds depth in front of the lens, and wider focal lengths have a broader field of view. If you plan to use the holder at its widest setting, test for vignetting before a critical shoot. Stopping down the aperture can sometimes reduce visible vignetting, but it won't eliminate it entirely if the holder itself intrudes into the frame.
Step-by-step fitting guide
- Check your lens filter thread size: Look for the diameter symbol (Ø) followed by a number on the front of your lens or inside the lens cap. If it reads 49mm, you can use the P49 holder directly. If it reads 40.5mm or 46mm, you'll need the matching adaptor. If you can't find the thread size, measure the inner diameter of the lens front with a ruler or calipers.
- Choose the correct adaptor: Order the NiSi 40.5mm Adaptor for P49 Filter Holder if your lens thread is 40.5mm, or the NiSi 46mm Adaptor for P49 Filter Holder if it is 46mm. Both adaptors step up to 49mm, so the holder fits either way. Don't force an adaptor that doesn't thread smoothly—it may cross-thread and damage the lens.
- Attach the adaptor to your lens: Screw the adaptor onto your lens filter thread clockwise until it is snug. Avoid over-tightening, as this can make removal difficult later. If the adaptor feels loose, check for dirt on the threads and clean with a soft brush.
- Mount the P49 filter holder: Align the holder's mounting ring with the adaptor's 49mm thread and rotate clockwise until it seats firmly. The holder should sit flush against the adaptor. Give the holder a gentle tug to confirm it's secure before adding filters.
- Insert your square filters: Slide up to two NiSi P1 square filters into the holder's slots. Use the 360-degree rotation to adjust the filter angle as needed. Check that filters are fully inserted and won't slip out when you rotate the holder.
- Test for vignetting: Take a test shot at your widest focal length and aperture. Review the corners for darkening; if vignetting is present, try stopping down or removing a filter. Vignetting may be unavoidable on some wide lenses—plan compositions accordingly.
Product facts
- NiSi 40.5mm Adaptor for P49 Filter Holder: Aluminum-alloy step-up adaptor from 40.5mm to 49mm. It lets you mount the P49 holder on lenses with a 40.5mm filter thread without needing a separate step ring.
NiSi 40.5mm Adaptor for P49 Filter Holder - NiSi 46mm Adaptor for P49 Filter Holder: Aluminum-alloy step-up adaptor from 46mm to 49mm. It converts a 46mm lens thread to the 49mm mount required by the P49 holder.
NiSi 46mm Adaptor for P49 Filter Holder - NiSi P49 49mm Filter Holder for Compact Cameras: Accepts two square filters from the NiSi P1 range and offers 360-degree rotation. You can stack and rotate filters independently, which is useful for graduated ND or polarizing effects.
