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Comparison of rectilinear versus rectilinearized
111° hAOV of Start - Centre - APS-C edge - Edge - Summary The Sigma AF 12-24 f:4.5-5.6 EX DG is often criticized for poor sharpness, but the truth is that for such a lens providing such a wide field of view it is really quite admirably sharp. And there is currently (April 2007) no other lens commercially available that provides an equally wide field of view, not even a prime lens. The Canon EF 15 mm f/2.8 fisheye compares quite favourably in the centre and what corresponds to the APS-C edge, but it can not compete at the far edge. The Sigma AF 8 mm f/4.0 EX due to its smaller image projection circle really has no chance of providing a resolution similar to the other two lenses. So, while the rectilinear by design Sigma 12-24 mm zoom provides the best overall resolution at 111° hAOV the rectilinear remapped images from the fisheye lenses would suffice for smaller reproductions. However, if appropriate for the particular use images from these lenses are best remapped to some projection other than rectilinear, i.e. the rectangular projection provided by RectFish. In this way the fisheye lenses can provide sharp images with a much wider field of view than even the Sigma 12-24 mm zoom. AcaPixus, April 2007
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Copenhagen Botanical Garden greenhouse
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