What it defines
A thread diameter in millimeters, such as 52, 58, 67, 72 or 82 mm.
What it does not promise
The diameter says nothing about filter quality or vignetting on wide lenses.
Where it turns up
The Nikon 55-300mm and Nikon 50mm f/1.8G take 58 mm; the Sony 18-105mm takes 72 mm; the TTArtisan 500mm takes 82 mm. The NEEWER M22 ring light screws onto 67 mm threads.
How to check before buying
Read the diameter on your lens before buying filters or thread-on accessories.
What people ask before they commit
Where do I find my lens’s filter size?
Usually printed on the lens barrel or cap, often with a ⌀ symbol, and on the lens listing.
Can I use a filter of a different size?
With a step-up or step-down ring.
Do all lenses take filters?
No. Some ultra-wides have bulging front elements; the [TTArtisan 10mm F2](/reviews/wide-angle-lenses-ttartisan/) includes a 72 mm filter holder instead.
Last reviewed November 2, 2026