Quick answer
The Mamiya /Sekor SX 55mm f/1.8 is a standard prime lens covering 55mm at f/1.8 for the M42 mount. Its fast maximum aperture helps in dim light and gives good subject separation.
About this lens
The Mamiya /Sekor SX 55mm f/1.8 is a fast manual-focus standard prime lens covering 55mm at f/1.8 for M42 mount cameras. The natural field of view suits street, documentary and everyday photography.
Mamiya /Sekor SX 55mm f/1.8 specifications
What can you shoot with the Mamiya /Sekor SX 55mm f/1.8?
At 55mm this is a standard prime, which typically suits:
- Everyday and street photography
- Natural-perspective portraits
- Documentary and travel work
Its fast maximum aperture helps in dim light and gives good subject separation.
Full-frame equivalent and field of view
Calculated from the focal length and crop factor (adapted mount, so sensor size depends on your camera). Not measured.
| Sensor | Crop | Equivalent | Horizontal FOV | Diagonal FOV |
|---|---|---|---|---|
| Full frame | 1.0x | 55mm | 36.2° | 42.9° |
| APS-C | 1.5x | 83mm | 24.6° | 29.4° |
| Micro Four Thirds | 2.0x | 110mm | 18.6° | 22.3° |
Frequently asked questions
What mount does the Mamiya /Sekor SX 55mm f/1.8 use?
It uses the M42 mount, so it fits M42 cameras directly and can be used on other systems through a mount adapter.
What is the focal length of the Mamiya /Sekor SX 55mm f/1.8?
It is a fixed 55mm lens with a maximum aperture of f/1.8. That makes it a standard lens.
Is the Mamiya /Sekor SX 55mm f/1.8 a prime or a zoom lens?
It is a prime lens with a fixed 55mm focal length. Primes usually open wider than zooms; this one opens to f/1.8.
What is the Mamiya /Sekor SX 55mm f/1.8 equivalent on a crop sensor?
On APS-C (1.5x crop) it frames like 83mm on full frame, with a 24.6° horizontal and 29.4° diagonal field of view. On Micro Four Thirds (2x crop) it frames like 110mm on full frame, with a 18.6° horizontal and 22.3° diagonal field of view. These figures are calculated from the focal length and crop factor.
Alternatives for M42 from other brands
All M42 lensesSame mount, overlapping focal range, closest maximum aperture first.