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Production
-
Country
East Germany
Optical
6 elements in 4 groups
Updated
Feb 15, 2026
Carl Zeiss Jena Flektogon 20mm f/4
M42
Overview
The Carl Zeiss Jena Flektogon 20mm f/4 pushed ultra-wide photography into accessible territory. In an era when 20mm lenses were exotic and expensive, Zeiss Jena delivered one that worked. The Flektogon formula adapted well to extreme wide-angle, though the f/4 aperture reflected the optical challenges. For landscape and architectural photographers behind the Iron Curtain and beyond, this was the ultra-wide solution.
Verdict: An accessible ultra-wide from the East German Zeiss era. Not perfect, but it delivers the 20mm perspective at a reasonable price. For M42 shooters wanting to go really wide, it's a solid option.
Community Insights
What people love
- Affordable ultra-wide for M42
- Dramatic 20mm perspective
- Better edge performance than expected
- Zeiss Jena build quality
- Unique focal length
What people dislike
- f/4 slow — needs good light
- Barrel distortion
- Heavy vignetting wide open
- Flare-prone without hood
- Not many adapters work (rear element clearance)
Pro Tips
- Always use a hood
- Stop down to f/8 for landscapes
- Check adapter clearance before buying
- Great for dramatic architectural shots
Sources (1)
Lens Heritage 2nd JSONsecondary
The Carl Zeiss Jena Flektogon 20mm f/4 pushed ultra-wide photography into accessible territory. In an era when 20mm lenses were exotic and expensive, Zeiss Jena delivered one that worked. The Flektogon formula adapted well to extreme wide-angle, though the f/4 aperture reflected the optical challenges. For landscape and architectural photographers behind the Iron Curtain and beyond, this was the ultra-wide solution.