Photo: Gisling (CC BY-SA 4.0)
Quick answer
The Carl Zeiss Jena Flektogon 20mm f/4 is a ultra-wide prime lens covering 20mm at f/4.0 for the M42 mount. Its moderate maximum aperture works best in good light or with a higher ISO.
About this lens
The Carl Zeiss Jena Flektogon 20mm f/4 is a manual-focus wide-angle prime lens covering 20mm at f/4 for M42 mount cameras. The wide view suits landscapes, architecture and environmental shots.
Carl Zeiss Jena Flektogon 20mm f/4 specifications
- Brand
- Carl Zeiss
- Mount
- M42
- Focal length
- 20mm
- Maximum aperture
- f/4.0
- Lens type
- Prime
What can you shoot with the Carl Zeiss Jena Flektogon 20mm f/4?
At 20mm this is a ultra-wide prime, which typically suits:
- Landscapes and big skies
- Architecture and interiors
- Astrophotography and night skies
Its moderate maximum aperture works best in good light or with a higher ISO.
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 | 20mm | 84° | 94.5° |
| APS-C | 1.5x | 30mm | 61.9° | 71.6° |
| Micro Four Thirds | 2.0x | 40mm | 48.5° | 56.8° |
Frequently asked questions
What mount does the Carl Zeiss Jena Flektogon 20mm f/4 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 Carl Zeiss Jena Flektogon 20mm f/4?
It is a fixed 20mm lens with a maximum aperture of f/4.0. That makes it a ultra-wide lens.
Is the Carl Zeiss Jena Flektogon 20mm f/4 a prime or a zoom lens?
It is a prime lens with a fixed 20mm focal length. Primes usually open wider than zooms; this one opens to f/4.0.
What is the Carl Zeiss Jena Flektogon 20mm f/4 equivalent on a crop sensor?
On APS-C (1.5x crop) it frames like 30mm on full frame, with a 61.9° horizontal and 71.6° diagonal field of view. On Micro Four Thirds (2x crop) it frames like 40mm on full frame, with a 48.5° horizontal and 56.8° 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.
