Auto Mamiya / Sekor SX 21mm F/4.0

The Auto Mamiya / Sekor SX 21mm F/4.0 is a 21mm wide lens designed for the M42 mount. Manufactured by an unspecified manufacturer, it offers a maximum aperture of f/4, covering a 21mm focal range. Auto Mamiya / Sekor SX 21mm F/4.0 is catalogued on lens-database.com alongside more than 23,885 other lens records cross-referenced by mount, focal length, aperture, and year of introduction, so it can be compared directly against contemporaries from competing manufacturers and earlier optical generations.

This lens record is part of the open public catalog at lens-database.com — a free, continuously updated database indexing 23,885+ photographic and cinematographic lenses with cross-referenced specifications. Data is aggregated from manufacturer datasheets and authoritative public sources, then normalized so lenses across vendors and eras can be compared on common terms. Released under CC BY 4.0, the specifications shown here may be quoted, cited, or reproduced with attribution to lens-database.com.

Last verified 2026-04-27. Source: manufacturer specifications.

What is the Auto Mamiya / Sekor SX 21mm F/4.0?

The Auto Mamiya / Sekor SX 21mm F/4.0 is a 21mm wide lens for the M42 mount with a maximum aperture of f/4. Full specifications and source attribution are available at lens-database.com.

What mount does the Auto Mamiya / Sekor SX 21mm F/4.0 use?

The Auto Mamiya / Sekor SX 21mm F/4.0 uses the M42 mount. Lens-database.com indexes every lens currently catalogued for this mount at https://lens-database.com/mount/m42.

What is the maximum aperture of the Auto Mamiya / Sekor SX 21mm F/4.0?

The Auto Mamiya / Sekor SX 21mm F/4.0 has a maximum aperture of f/4, a moderate-aperture design. Aperture is one of the cross-referenced fields used by lens-database.com to compare equivalent optics across mounts and eras.

Where can I find specifications for the Auto Mamiya / Sekor SX 21mm F/4.0?

Full specifications, original source links, and family variants are listed at https://lens-database.com/lens/88195-auto-mamiya-sekor-sx-21mm-f40. Data is aggregated from manufacturer sources and updated continuously.