M42 Screw Mount vs. Nikon Z
Comparing 2 standards across 12 specifications. 12 key differences identified.
The M42 Screw Mount (also known as the Universal Screw Mount or Praktica/Pentax Thread, standardized under DIN 4503) is a standardized metric threaded lens interface featuring an M42 × 1.0 mm thread pitch and a 45.5 mm Flange Focal Distance. Popularized by Asahi Pentax Spotmatic and Soviet Helios-44 lenses, it is the most adapted vintage manual lens standard in mirrorless photography.
The Nikon Z Mount (introduced in 2018 for the Z-series mirrorless system) features the shortest Flange Focal Distance (16.0 mm) and the widest inner throat diameter (55.0 mm) among current major full-frame mirrorless mounts (Sony E, Canon RF, Leica L). This geometry enables extreme optical designs, including the ultra-fast NIKKOR Z 58mm f/0.95 S Noct.
Specification Comparison Table
12 Parameters| Parameter / Spec | ||
|---|---|---|
|
Flange Focal Distance (FFD)
|
45.50 mm (1.791 in) | 16.00 mm (0.630 in — the shortest FFD among current major full-frame mirrorless mounts) |
|
Thread Dimensions
|
M42 × 1.0 mm metric thread (42.0 mm diameter with 1.0 mm thread pitch) | — |
|
Mounting Style
|
Direct screw-in thread (approx. 2 to 3 full revolutions to seat against flange) | — |
|
Aperture Pin Mechanism
|
Center spring-loaded pin pressed by camera stop-down lever to close iris during exposure | — |
|
Benchmark Cameras & Lenses
|
Pentax Spotmatic (Super-Takumar / SMC Takumar), Praktica L-series, Zenit-E (Helios-44-2 58mm f/2), Carl Zeiss Jena | — |
|
Mirrorless Adaptability
|
Adapted seamlessly to Sony E, Canon RF, Nikon Z, L-mount, Fuji X, and MFT via inexpensive passive aluminum rings | — |
|
Inner Throat Diameter
|
— | 55.00 mm (2.165 in — the largest throat diameter among current major full-frame mirrorless mounts) |
|
Bayonet Tabs
|
— | 4 asymmetrical locking tabs with counter-clockwise twist (traditional Nikon direction) |
|
Electronic Interface
|
— | 11 gold-plated contact pins |
|
Max Theoretical Aperture
|
— | Mount geometry (throat diameter and FFD) permits faster designs than F-mount allowed; the fastest lens actually shipped is the Z 58mm f/0.95 S Noct -- claims of a precise theoretical f/0.58 limit are back-of-envelope extrapolations, not a published Nikon figure |
|
Legacy F-Mount Adaptability
|
— | Nikon FTZ / FTZ II adapter (30.5 mm spacer) provides full AF/AE with AF-S and AF-P NIKKOR lenses |
|
Camera Systems
|
— | Nikon Z9, Z8, Z7 II, Z6 III, Zf (full frame), Z50, Zfc, Z30 (DX APS-C) |