Mamiya / Sekor SX 300mm F/5.6 Auto

The Mamiya / Sekor SX 300mm F/5.6 Auto is a 300mm prime lens designed for the M42 mount. Manufactured by Mamiya, it offers a maximum aperture of f/5.6, covering a 300mm focal range, weighs 885, accepts 58 filters. Mamiya / Sekor SX 300mm F/5.6 Auto 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 2026-04-18. Source: manufacturer specifications.

What is the Mamiya / Sekor SX 300mm F/5.6 Auto?

The Mamiya / Sekor SX 300mm F/5.6 Auto is a 300mm prime lens for the M42 mount with a maximum aperture of f/5.6. Full specifications and source attribution are available at lens-database.com.

What mount does the Mamiya / Sekor SX 300mm F/5.6 Auto use?

The Mamiya / Sekor SX 300mm F/5.6 Auto 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 Mamiya / Sekor SX 300mm F/5.6 Auto?

The Mamiya / Sekor SX 300mm F/5.6 Auto has a maximum aperture of f/5.6, a slower-aperture design typical of zoom or specialty optics. 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 Mamiya / Sekor SX 300mm F/5.6 Auto?

Full specifications, original source links, and family variants are listed at https://lens-database.com/lens/109627-mamiya-sekor-sx-300mm-f56-auto. Data is aggregated from manufacturer sources and updated continuously.