The Fullframe Fisheyes: Sigma 8mm and 15mm

Sigma 8mm f/3.5 Circular Fisheye, Sigma 15mm f/2.8 Fisheye, Sigma 12-24 EX DG. Click here to enlarge.

Fisheyes are unique lenses. Unlike all other lenses, they don't try to correct the distortion, so they can achieve an amazing angle of view of 180 degrees! Actually, there have been even fisheye lenses with an angle of view of 220 degrees, as the incredible Nikkor 6mm f/2.8, but the majority of fisheye lenses currently on the market at 180 degrees fisheyes.

Sigma produces four fisheye lenses: the 8mm and 15mm, for FF cameras, and the 4.5mm and 10mm, for APS-C cameras. In this article, I have tested the fullframe fisheyes, on my 21 megapixels 1DsIII; for comparison, I have taken some shots even with my 12-24, that is the widest rectilinear (non-fisheye) wideangle currently in production.

Phisically, the two fisheyes are very similar, except for the lens hood of the 15mm: the 8mm has a 180 degrees angle of view in every direction, so it has no lens hood, otheriwise it would inevitably be included in every photo. They are pretty small - much smaller than the 12-24, they are light and well built, as all Sigma EX lenses. Unlike the Sigma 12-24 and the newer 4.5 and 10mm, the two fullframe fisheyes have a traditional AF motor: it is not silent as HSM and it has not full time manual focus, but it is as fast as the other wide-angle's AF. Nearly all super wide-angles have fast autofocus, and the 8mm and 15mm are no exception!

Specifications

Angle of view

I have photographed my car from the same point of view with the 12-24mm at 12mm, with the 15mm and with the 8mm.

Sigma 12-24 EX DG

Sigma 15mm f/2.8 Fisheye

Sigma 8mm f/3.5 Circular Fisheye

The 12-24 has an awesome angle of view of 120 degrees; of course it is not as wide at the 15mm, but it is perfectly rectilinear. The 15mm instead has the classic "fisheye distortion", and it offers and angle of view of 180 degrees on the diagonal.

The 8mm is a circular fisheye: it does not cover the entire frame, but it creates a circle in the center of the image. It has a 180 degrees angle on all sides: it is so wide that it is almost impossible to exclude the tripod from the composition!

Image quality comparison

These are some 100% crops from the previous photos, converted with ACR with no sharpening, minimum contrast, and without any other enhancement.

	center	extreme corner
8
15
12

In term of sharpness, all the three lenses are very sharp in the center; the 12-24mm and the 8mm are quite sharp even in the corners, while the 15mm has less corner sharpness (but only the extreme corners are so soft). The two fisheye have clearly more chromatic aberration than the 12-24; you can easily correct the CA with Adobe Camera RAW.

Samples

These are a couple of sample photos that I have taken to evaluate the image quality of the lenses.

Canon 1DsIII, Sigma 8mm f/3.5 EX DG Circular Fisheye, 1/60 f/9, ISO 100. Click here to download full size photo.

Canon 1DsIII, Sigma 15mm f/2.8 EX DG Fisheye, 1/30 f/5.6, ISO 100. Click here to download full size photo.

In my opinion, both the 8mm and the 15mm gives excellent image quality. Chromatic aberration has been eliminated with Photoshop, and the sharpness is great! 

Conclusions

Fisheye are not easy to use, but they can give very cool results, with some practice and creativity. If you are looking for a fullframe fisheye, both the Sigma 8mm and 15mm are excellent choices! Price and image quality are on par with the Canon 15mm (I have not had the occasion to make a side by side comparison, but I have tried the Canon some time ago); the Sigma fisheyes have better built quality and better macro ratio than their Canon equivalent. In particular, the 15mm has a macro ratio of 1:3.8, that allows to take very cool photos of small animals into their environment.

Do you have comments or questions?

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