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Lens review

Samyang 12 mm f/2.8 ED AS NCS Fish-eye

30 December 2014
Szymon Starczewski

8. Vignetting

While working on APS-C/DX sensors the vignetting won’t cause you any problems and the thumbnails below show it pretty well.

Samyang 12 mm f/2.8 ED AS NCS Fish-eye - Vignetting


Our measurements confirm that observation – at the maximum relative aperture the vignetting reaches only 20% (−0.64 EV) and it decreases to 11% (−0.33 EV) after applying f/4.0. Stopping down the aperture by next 1 EV makes the brightness loss in the corners imperceptible as it is just 6% (−0.19 EV).

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It’s worth mentioning that using the Samyang 12 mm f/2.8 ED AS NCS Fish-eye on APS-C/DX sensors is not only a quite sensible idea but also the best way of getting a really wide angle of view with a low vignetting level. The stereographic mapping used in the Samyang allows a 1.5x sensor achieve an angle of view of almost 125 degrees (if you wanted to get the same value using a rectilinear lens you would have to deal with a 7.5 mm focal length). Other mapping functions won’t allow you such an achievement as other fisheye lenses come with 15-16 mm focal lengths. For example after attaching the old, good Zenitar 2.8/16 (which, on full frame, like the Samyang, has an angle of view of 180 degrees) to a camera with the APS-C/DX sensor you have a field of view of less than 100 degrees at your disposal.

Even the biggest, flat and evenly lit vignetting testing chart is too small for a fisheye lens tests on full frame. The photos we took in our studio along with photos of night sky we took outside allowed us to compute roughly the vignetting level of the tested lens. One glance at photos from the Samyang let you know that this problem is not huge. It seems that even at the maximum relative aperture in frame corners the lens doesn’t loses more than 1.2 EV.

Samyang 12 mm f/2.8 ED AS NCS Fish-eye - Vignetting