How to Pick the Right Adapter Ring for the NiSi M75 System
By NiSi Filters Australia | Published: 2026-10-31
Category: How-to Guides
Match your lens thread to the NiSi M75 system, choose between a standard adapter and the 67mm main ring, and avoid the most common sizing mistakes.
Quick answer
Check your lens filter thread and choose the M75 adapter ring that matches it exactly: 43mm, 67mm, or 72mm. The 67mm main adaptor ring is also the spare part if you already own the M75 holder and need a replacement.
Why the thread size is the only number that matters
The NiSi M75 system uses a holder that accepts 75mm-wide filters, but the holder attaches to your lens through an adapter ring. That ring screws into the front filter thread of your lens, so the thread diameter must match precisely. A 72mm lens needs a 72mm adapter; a 43mm lens needs a 43mm adapter. There is no universal ring that covers multiple thread sizes without step-up rings, which add bulk and can cause vignetting on wide lenses.
If you already own the M75 holder kit, it includes a 67mm main adaptor ring. That ring is the core connection point for the holder. The 43mm and 72mm adapters are separate rings that let you use the same holder on lenses with those thread sizes.
When to buy the 67mm main adaptor ring as a spare
The 67mm main adaptor ring is not just another size option—it is the part that comes with the NiSi M75 holder. If you lose or damage your original ring, or if you want to keep one mounted on a second lens for faster changes, the spare part is the correct replacement. It is made from corrosion-resistant anodized aluminum, so it is built to withstand regular outdoor use.
Do not buy the 67mm main adaptor ring expecting it to fit a lens with a different thread size. It only fits lenses with 67mm filter threads. For other sizes, choose the matching adapter.
What about step-up rings and third-party adapters?
You can use a step-up ring to convert a smaller lens thread to 67mm and then use the main adaptor ring, but this adds an extra connection that can loosen or introduce play. For critical landscape work, especially with heavy filters, a dedicated adapter ring for your lens size is more secure. NiSi offers dedicated 43mm and 72mm adapters for the M75 system, so you can avoid stacking rings when your lens matches those sizes.
Steps to choose your M75 adapter ring
- Find 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 is not visible, check the lens manual or the manufacturer's website. Common sizes include 43mm, 67mm, and 72mm. Do not guess—measure or verify the exact thread diameter before ordering.
- Match that number to an M75 adapter: Choose the NiSi 43mm adaptor for 43mm threads, the NiSi 72mm adapter for 72mm threads, or the 67mm main adaptor ring for 67mm threads. If your lens has a different thread size, you will need a step-up ring to reach one of these sizes. A 67mm main adaptor ring is the standard ring included with the holder; only buy it separately if you need a spare.
- Decide between a dedicated adapter and a step-up ring: If your lens thread matches 43mm, 67mm, or 72mm, use the dedicated adapter for the most secure fit. If your lens is another size, use a step-up ring to the nearest supported size, but be aware that stacking rings can increase the chance of vignetting on wide-angle lenses. For focal lengths wider than about 24mm, test for vignetting before relying on a step-up ring.
- Check the adapter type before buying: The 67mm main adaptor ring is a spare part for the M75 holder and is already included in the kit. The 43mm and 72mm adapters are add-on rings for those specific thread sizes. Do not buy the 67mm ring if you already have the kit unless you need a backup. Confirm whether you need a replacement or an additional size—this avoids duplicate purchases.
M75 adapter options at a glance
- NiSi 43mm adaptor for NiSi M75 75mm Filter System: Aluminum-alloy adaptor for lenses with 43mm filter threads. Ideal for compact cameras or small lenses that would otherwise need a step-up ring.
NiSi 43mm adaptor for NiSi M75 75mm Filter System - NiSi 67mm Main Adaptor Ring for M75 (Spare Part): Spare 67mm main adaptor ring, already included with the M75 holder. Buy this only as a replacement or second ring, not as an upgrade for a different thread size.
NiSi 67mm Main Adaptor Ring for M75 (Spare Part) - NiSi 72mm Adapter for NiSi M75 75mm Filter System: Aluminum-alloy adapter for lenses with 72mm filter threads. Lets you use the M75 holder on many standard zoom and prime lenses without extra step-up rings.
