Sigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM
Quick answer
The Sigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM is a ultra-wide fisheye lens covering 4mm at f/2.8 for the Pentax K mount. Its bright maximum aperture handles indoor and evening light reasonably well.
- APS-C (6.8mm equiv.)
- 29 Pentax K cameras
- Focal
- 4.5mm
- Aperture
- f/2.8–22
- Min focus
- 0.14m
- AF motor
- HSM
What 4mm sees
- APS-C crop 1.5× → 6.8mm
- 145.3° 138.9° horizontal
Diagonal angle of view. Frames drawn to scale at 4.5mm. Calculated from the focal length and crop factor, not measured.
Open the field-of-view calculatorSigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM specifications
Optics
- Focal length
- 4mm
- Maximum aperture
- f/2.8
- Minimum aperture
- f/22
- Format coverage
- APS-C
- Optical construction
- 13 elements in 9 groups
- Aperture blades
- 6
Focus
- Autofocus motor
- HSM
- Minimum focus distance
- 0.14 m
- Maximum magnification
- 0.17×
Specification source: sigma-global.com
What can you shoot with the Sigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM?
At 4mm this is a ultra-wide fisheye, which typically suits:
- Landscapes and big skies
- Architecture and interiors
- Astrophotography and night skies
Its bright maximum aperture handles indoor and evening light reasonably well.
Frequently asked questions
What mount does the Sigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM use?
It uses the Pentax K mount, so it fits Pentax K cameras directly.
What is the focal length of the Sigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM?
It is a fixed 4mm lens with a maximum aperture of f/2.8. That makes it a ultra-wide lens.
Is the Sigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM a prime or a zoom lens?
It is a prime lens with a fixed 4mm focal length. Primes usually open wider than zooms; this one opens to f/2.8.
What is the Sigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM equivalent on a crop sensor?
On APS-C (1.5x crop) it frames like 6.8mm on full frame, with a 138.9° horizontal and 145.3° diagonal field of view. These figures are calculated from the focal length and crop factor.
Which cameras does the Sigma 4.5mm f/2.8 EX DC CIRCULAR FISHEYE HSM fit?
Any Pentax K-mount camera, including Pentax *ist DL, Pentax *ist DS, Pentax K-01, Pentax K-1, and Pentax K-3 and 24 more.
