49 mm Lens Filter Thread (M49 × 0.75)
Direct Answer
The 49 mm Filter Thread (M49 × 0.75 mm metric pitch) is the compact mirrorless prime standard, popularized across Sony FE compact G primes (24mm, 40mm, 50mm f/2.5 G), the Sony Zeiss Sonnar 55mm f/1.8 ZA, and Fujifilm X100-series leaf-shutter street cameras (via AR-X100 adapter).
Source: DIN 4503 / Sony & Fujifilm Technical Notes
Specs
| Thread Diameter | 49.0 mm (nominal ø49) |
| Metric Thread Pitch | 0.75 mm (M49 × 0.75) |
| Compact Street Photography Standard | Fujifilm X100V / X100VI (requires 49mm filter adapter ring AR-X100 for weather sealing) |
| Notable Glass | Sony FE 55mm f/1.8 ZA, Sony FE 24mm f/2.8 G, Sony FE 40mm f/2.5 G, Sony FE 50mm f/2.5 G, Pentax SMC DA 35mm/70mm Limited |
Fujifilm X100 Weather Sealing
On the Fujifilm X100 series, the front lens element moves during focusing. Screwing a 49 mm protective/UV filter onto the AR-X100 adapter ring seals the front barrel against moisture and dust ingress, achieving full IP weather resistance.