Sigma 15mm f/2.8 Diagonal Fisheye

Sigma 15mm F2.8 EX DG Diagonal Fisheye

Physical Characteristics

  • Available Mounts: Canon EF, Nikon F, Sigma SA, Pentax K
  • Lens type: Fisheye (Diagonal on full frame)
  • Focus type: Manual or auto
  • Aperture range: f/2.8 – f/22
  • Filter size: n/a
  • Dimensions (with caps on): 89mm high, 75mm wide
  • Height (from camera front to lens front; caps off): 68mm
  • Weight (with caps on): 384g / 14 oz.
  • Weight (with caps off): 338g / 12 oz.
  • Other: fixed plastic lens shade

Star Tests

2 min. single exposure at f/2.8, ISO 1600, Canon EOS Ra, Bortle 3 sky.
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Same image at f/2.8 with 200% zoomed-in crop boxes showing star performance. Lots of coma, vignetting, and loss of sharpness away from center. Typical chromatic abberation. Note: the lens was so short that I think my dew strap interfered and created some artificial vignetting in the extreme corners. Open full-size image in new tab.
2 min. single exposure at f/3.5, ISO 1600, Canon EOS Ra, Bortle 3 sky.
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Same image at f/3.5 with 200% zoomed-in crop boxes showing star performance. Fairly similar to f/2.8, coma is improved, but still very noticeable. Note: the lens was so short that I think my dew strap interfered and created some artificial vignetting in the extreme corners. Open full-size image in new tab.
2 min. single exposure at f/4, ISO 1600, Canon EOS Ra, Bortle 3 sky.
Open full size image in new tab.
Same image at f/4 with 200% zoomed-in crop boxes showing star performance. Slight improvements with the coma, still pretty bad though. Vignetting is improved significantly. Note: the lens was so short that I think my dew strap interfered and created some artificial vignetting in the extreme corners. Open full-size in new tab.
4 min. single exposure at f/4.5, ISO 1600, Canon EOS Ra, Bortle 3 sky.
Open full-size image in new tab.
Same image at f/4.5 with 200% zoomed-in crop boxes showing star performance. No visible improvement from f/4. Note: the lens was so short that I think my dew strap interfered and created some artificial vignetting in the extreme corners. Open full-size image in new tab.
4 min. single exposure at f/5.6, ISO 1600, Canon EOS Ra, Bortle 3 sky.
Open full-size image in new tab.
Same image at f/5.6 with 200% zoomed-in crop boxes showing star performance. Coma not much better than f/4. Dimmer stars are a bit sharper. Note: the lens was so short that I think my dew strap interfered and created some artificial vignetting in the extreme corners. Open full-size image in new tab.

Commentary

This lens was a bit of a disappointment considering the price. The star distortion known as ‘coma’ which makes the stars look triangular away from center was pretty bad at all focal ratios tested. The vignetting and loss of sharpness was also very noticeable until about f/4, which is where I would use this lens. Lastly, I didn’t like how short this lens is. I didn’t have a dew strap that was narrow enough for the tiny height of this lens so unfortunately the dew strap interfered with the images, which I didn’t notice until the next day, and couldn’t re-do the test.

Price

$609 USD (December 2020)

Sigma 15mm F2.8 EX DG Diagonal Fisheye
Reader Rating0 Votes
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Pros
Small and lightweight
Cons
Significant coma away from center at all focal ratios tested
Expensive
75
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