N°106717 · Family detail
MamiyaWide·M42 mount·1974
Auto Mamiya/Sekor SX 21mm F/4
Specifications01
MountM42
Focal length21mm
Max aperturef/4
TypeWide · Prime
Release year1974
Weight220 g
Filter size58 mm
Min focus distance0.45 m
Aperture blades5
Optical elements9
Groups8
AutofocusNo
StabilizationNo
Aperture controlAperture ring (Manual settings only)
Lens hoodNot available
TeleconvertersNot available
EraFilm era
Production statusDiscontinued
Additional Info02
Lens TypeUltra-wide angle prime lens
Summary02
Auto Mamiya/Sekor SX 21mm F/4 is a 21mm prime wide-angle lens for M42 mount, intended for wide-area landscape and general photography. It uses a fixed maximum aperture of f/4.
AI-assisted summary — verify against linked sourcesWhere can this lens be adapted?
The M42 screw mount has a flange distance of 45.46 mm. A plain adapter fits a camera whose flange distance is at least 1.46 mm shorter. How lens adapters work
- Many M42 lenses close the aperture only when a pin at the rear is pressed. Use an adapter that presses the pin, or set the A/M switch to M.
- Sony EAdapter · 27.46 mm
- Canon RFAdapter · 25.46 mm
- Nikon ZAdapter · 29.46 mm
- Fujifilm XAdapter · 27.76 mm
- L-MountAdapter · 25.46 mm
- Micro Four ThirdsAdapter · 26.21 mm
- Fujifilm G (GFX)Adapter · 18.76 mm
Covers full-frame: it can vignette on a medium format sensor.
- Canon EF-MAdapter · 27.46 mm
- Canon EFAdapter · 1.46 mm
A rear element that sticks out can hit the camera mirror.
No plain adapter reaches infinity focus on: Nikon F.
Other Mounts03
No alternate mounts are indexed for this family yet.